by
Duncan Miller

Inspired by an article by Pavel Martynov on mindat.org I have been experimenting with taking stereoscopic pair photographs of an otherwise rather uninteresting mineral specimen, so that it can be viewed in 3D. It is really simple. All you need do is rotate the specimen through five degrees, without otherwise changing its relationship to the camera, and taking two photographs of it. Then you swap the righthand photo for the left one, and view the pair by squinting. You can p...

by Duncan Miller

South Africa is famous for its gems and minerals, and visitors sometimes imagine they can pick diamonds off the soles of their shoes. Gold nuggets roll down streams and platinum can be picked out of some of the oldest rocks on Earth. This is all fantasy of course. The platinum, gold and diamond mines are so regulated that throughout their lives most South Africans never see native gold, or platinum, or an uncut diamond; and possessing them without a permit is a criminal offe...

Duncan Miller

"Their dress consists of all kinds of beautifully prepared skins...gorgeously ornamented with copper beads...Their locks they thread with copper beads, covering their heads all over.  Around their necks they have chains, slung round them 15 or 16 times.  Many have round copper plates suspended from these chains.  On their arms they have chains of copper and iron beads which go round their bodies 30 or 40 times.  Their legs are encased in plaited skins, ornamented with beads......

Duncan Miller

There are several different mechanisms for garnets to show a change of colour. The most common of these is analogous to the colour change in the well-known alexandrite variety of chrysoberyl. This is due to differential transmission of different wavelengths of visible light, leading to a difference in perceived colour under lighting with different degrees of red or blue light. A less well-known type of colour change in gemstones is the so-called Usambara effect, named after t...

Lesley Andrews

Garnets are not only attractive, but also useful. As residents of the Cape, many of us know about the use of garnets as markers in diamond exploration. Other examples include garnet use in sandpaper, especially for wood sanding, and the production of synthetic garnets for laser generation.

The colours of garnet group minerals and varieties is a complex subject. Not all garnets are red, in fact they are found in all colours except bright blue. Briefly, the most common ions inf...

by
Peter Rosewarne

This month we are checking out the garnet group of minerals, which most people will have come across in the form of jewellery, as mineral specimens and even in mundane articles such as sandpaper. The previous fluorite article started with some “C” words that apply to the mineral and in the same vein, the following apply to garnets, with some qualifiers; cubic, contain calcium (some), colourful (some), cleavage-free, conchoidal fracture, costly (some), contain chrome ...

Jo Wicht

Who would have thought that some of the most boring looking mineral specimens could be the most spectacular under shortwave fluorescent light? Look at these three, for example…

 

 

 

Over time I have made a point of collecting specimens if I am aware that they fluoresce because that is fun, but often one acquires others unknowingly. Because I agreed to take some photos to supplement this edition of the MinChat, I shone my UV light over my entire mineral collection to see what I coul...

Duncan Miller

Cut rubies, red garnets and red glass can look very similar. There are several techniques that can be used to determine if a red stone is a ruby. These include a semi-destructive relative hardness test (ruby will scratch garnet and glass, but not the other way around); using a polariscope to test for birefringence (ruby is birefringent whereas glass and most garnet are not); and using a dichroscope to see the two pleochroic shades of red in ruby (which are absent in garnet and ...

Willie Lombard

I collect different species of minerals and rocks of SA and Namibia and need only one good example of each. Right across from the old Swanson Enterprises building in Springbok is an open yard with some large heaps of rocks and minerals. I asked the resident on the property if I could have a look-around. No problem. Found some fluorites and a good example of a diorite. There were some feldspars and a lot of pegmatites. I was sleeping over, so I asked the resident if I could ret...

Willie Lombard

On the shores of Lake Superior in the USA a fluorescent rock made headlines (on YouTube, anyway!). They call the normally drab rock a Yooper, after the locals from Upper Michigan. A geologist from the local university found that the sodalite in the rock causes the yellow fluorescence. I wish my sodalite would fluoresce like that! Those that do, produce only a very weak yellowish glow. On my way to the Groot Marico Gemboree in 2018 I decided to sleep over in the Pi...

By Peter Rosewarne

Introduction

The branch of mineralogy dealing with fluorescence apparently gained popularity in the 1930s with the availability of battery-powered portable ultraviolet (UV) lamps. The pioneer in producing such UV lamps and using them to prospect for and showcase minerals was Thomas S Warren, after whom the Thomas S Warren Museum of Fluorescence at Sterling Hill Mine Museum in the USA is named.

Those of you who have been paying attention to previous MinChat articles will ...

By Peter Rosewarne

Introduction

Have you ever wondered if there was a specimen out there that was the world’s best, or what the best six or ten mineral specimens ever discovered are considered to be? I thought it might be a bit of fun to put together a “Six of the Best” of the mineral kingdom based on expert opinion in respected publications, such as The Mineral Record and its supplements, Masterpieces of the Mineral Kingdom, and American Mineral Treasures. Some of these discoveries g...

by Peter Rosewarne

Fluorite: cubic, common, cheap (comparatively, but can be costly), contains calcium, and colourful, are some of the "C" words that can be used to describe this mineral. While good specimens of fluorite from classic localities aren’t cheap, most are cheaper than good specimens of ‘higher-end’ minerals such as azurite, dioptase, tourmaline and beryl and it is possible to build up a good collection of fluorites from worldwide localities. You are also likely to get a nice-...

Peter Rosewarne

Polished slabs and spheres don’t usually figure highly in my wish-list of mineral specimens but, over the years, some colourful and interesting ones have caught my eye and have been added to the Rosey Collection. This short article highlights some of what I hope you will agree are both unusual, interesting and colourful polished slabs from various localities around the world. The slabs very briefly described and illustrated herein are Sonora Sunrise and Laguna Agate from Me...

Lesley Andrews

I am the proud owner of two stone plants which I keep on the stoep table - these are decorated by a surface layer of small tumbled semi-precious stones. Recently I was astonished to see a threesome of Cape Turtle Doves on the table carefully picking out some of the stones, passing them to each other, rolling them around in their beaks and putting them down carefully all over the table. I knew that many birds eat grit, but why this preference for my ornamentals?

The Cape Turtle Do...

I do give myself complications.

Based on the success of the “September Spheres”, we invited photos of “royal blue” minerals for our October newsletter. This is because we are featuring Peter’s detailed article on lapis lazuli. Ultramarine is such a rich colour and there are not that many minerals of such a classic blue.

For my contribution, I photographed the few possibilities I had in my mineral cabinet, but thought a bit more. There was an odd offcut of stone in the outside cupb...

I first visited the Tucson shows in 1992. My intention was to buy faceting rough, but there was almost none I could afford, although the rand/dollar exchange rate was 6:1. One day, walking around with my friend and research colleague David Killick from the University of Arizona we wandered around, dazed and bewildered by the spectacular minerals from Afghanistan on display in one of the numerous tented venues. On one table, crowded with Afghan ethnic jewellery, possibly all modern, there sat ...

Lesley Andrews

Peter Carl Fabergé was born in St Petersburg in 1846, and eventually became Goldsmith to the Imperial Court of Russia, and a supplier of wonderful artworks worldwide. He assumed charge of the workshop his father had established in St Petersburg when he was only twenty-four years old, and presented the first Imperial Easter Egg to the Russian royal family in 1884. The workshop survived until 1918, by which time Russia had succumbed to revolution and the royal family was no mor...

Duncan Miller

After several years, or after many years, a gem cutter lands up with a junk box. Mine contains disappointing stones abandoned in disgust and partly-worked stones that came over the years with various faceting machines and batches of rough. As a lock-down project I decided to see what I could make from the contents of the faceting junk box. (There are another two – one with cabochons and another with broken synthetics. You never know, you know…)

To make it something of a ...

Malcolm Jackson

The Blue Lace Agate article by Jo and Duncan in last month’s Mineral Chatter inspired me to make a box and as I had some really nice pieces of Yellowwood around, I got sawing and made the box you see in the picture. I made the box 300 mm × 400 mm × 100 mm deep. I hope to catalogue the specimens and add some artwork. I also want to include Jo and Duncan’s article in a booklet format.

I wanted to house some of my Blue Lace Agate specimens that I had collected over many...

Duncan Miller

Peter Rosewarne

I’ve borrowed the title of a new coffee table book by Gerhard Wagner for this article as it seems appropriate in that the Tourmaline Group encompasses some 14 species currently and it is found in classic localities around the world. The idea for doing this article came from a comment from Jo that EXCO had raised tourmaline as a possible discussion topic. I also have and have had quite a few tourmaline specimens in my collection over the years and have attempted to limit dis...

by Jay and JD Haasbroek

I know for sure it was last year some time, but that’s about all I am prepared to admit to any sense of time or space in these times.

As was usual back then Verna Jooste was visiting round the kitchen table with me, and Jay was busy with stones in her adjacent cutting studio and joining the conversation every so often, with a stone in her hand. Verna, a teaching jeweller and artist, is always interested in the stone in the hand. She comes from a family of diamond c...

by Jo Wicht and Duncan Miller

For several decades small mines in southern Namibia have produced an attractive banded agate marketed as lapidary material. The major source has been a mine on Ysterputs farm, producing blue lace agate. It was promoted widely by the late George Swanson who owned the mine, so this material with its wavy blue and white lines is quite familiar. What is less well known is that the blue lace agate from Ysterputs is accompanied by several minerals forming aesthetic, c...

by Peter Rosewarne

 About a year ago I wrote an article on selling a mineral collection from South Africa, which was featured in the MinChat. One of the methods I listed, unsurprisingly, was setting up my own internet site. I didn’t go that route initially, relying on selling back specimens to dealers such as Hummingbird Minerals, John Betts Fine Minerals, Fabre Minerals and The Mineral Gallery, and some on Club Open Days. However, the former route seems to have run its course in terms of ...

Dave Hawes

I was lucky to be able to go on the trip that the club recently organised to the Richtersveld but unfortunately unable to attend the report back a few months later.

As I have been able to visit the area on numerous occasions, for a variety of reasons, since my first visit in the early 1980s I thought that I could share some of my experiences with the club.

While I had visited Namaqualand as a typical tourist to see the flowers, my first serious visit in the early 1980s was to del...

Mandy Freeman

With a sense of excitement and anticipation of the mineral treasures Madagascar offers, we boarded Air Madagascar on 1^st July this year (okay, 4 hours late, but at least on the same day). Our trip was part rock-hunting (obligatory in the Freeman household), and part island-holiday. Boy, were we in for a surprise…

We arrived in Antananarivo, capital of Madagascar where our adventures in a hired 4x4 with driver began. Tana, as it is known, has several stone markets where you...

by Mandy Freeman

During one of the excursions arranged at the 2019 Gemboree, a group of enthusiasts decided to split from the main convoy to return to Tubussis to spend a little more time looking at what this tiny village has to offer. The Green Dragon Mine is located near to Tubussis, and the area is known for good quality demantoid or green garnets. One of the vendors had laid out tables, which due to time constraints, the convoy missed on the first visit, and some very nice aquamarine spe...

‘Oh, oh, oh,
matchbox full of diamonds
pocket full of rain
I'm as happy as a hotel in the springtime
when the flowers bloom again’

David Kramer’s song about the Richtersveld starts on the road to Lekkersing: “O ja, vanaand stap ek alleen op die pad na lekka sing.”

It came bubbling into my brain the night we were briefed that we would be on the road to Lekkersing the next morning, deep in the Richtersveld, deep in diamond country, and it all seemed to make a new kind of sense. We w...

By Duncan Miller

How to teach yourself faceting, in three easy steps:

1.      Acquire a faceting machine. https://facetorsguild.com.au/About-Faceting-Machines

2.      Learn to facet. https://www.gemsociety.org/article/lapidary-fundamentals-gemstone-faceting/

3.      Become an expert. https://www.youtube.com/watch?v=oD6ZlNmtwmM&list=PLFIMjYf_BtnvaVZNQkHJ4ieF-v1fqPgqu&index=2

These are good introductory lessons for those starting out faceting, and perhaps don’t have access to a mentor or ...

By Peter Rosewarne

Duncan Miller

Initial dopping requires a flat surface on your rough. Prepare a flat dop with a blob of hot wax on it and in the transfer fixture push this against another flat dop face to form a layer of wax a few millimetres thick. You can build this up with several layers if the stone you are going to cut is very heat sensitive. Clean the flat on your rough with alcohol. When the wax is cold, apply a small drop of cyanoacrylate glue (CA), position the rough on the dop quickly, and let the gl...

Duncan Miller

These are the rhodochrosites (presumably from Hotazel) that I have been faceting, on and off, for the past two months. The ‘pink’ stones (on the left) are 0,65 ct; 0,68 ct; 1,46 ct; and 0,96 ct.  The ‘red’ stones (on the right) are 1,39 ct; 1,66 ct; and 1,71 ct. The rough was acquired more than twenty years ago as a small batch of broken and half-finished stones. A recent article about faceted rhodochrosite in The Journal of Gemmology inspired me to try to resurrect them...

According to https://en.wikipedia.org/wiki/Pseudomorph:

“In mineralogy, a pseudomorph is a mineral or mineral compound that appears in an atypical form (crystal system), resulting from a substitution process in which the appearance and dimensions remain constant, but the original mineral is replaced by another. The name literally means "false form". Terminology for pseudomorphs is "replacer after original", as in brookite after rutile.

A paramorph (also called allomorph) is a mineral chan...

By Peter Rosewarne

Sifting through my collection in order to catalogue and assess specimens more fully has got me thinking more about some of their mineralogical and crystallographic properties. Why are some examples of the same mineral one colour and others another? Why are some stubby and others prismatic? What crystal system do they each belong to? What is ilvaite or axinite or vivianite?

I’m fascinated by the interesting habits that some minerals exhibit which in many cases don’t see...

By Duncan Miller

(This is a follow-up to a previous article on faceting quartz, to be found with other faceting articles on the club’s website http://ctminsoc.org.za/articles/category/Faceting.) 

Every faceter knows quartz, those great big glassy-looking chunks that seem to cry out to be turned into doorknobs. Or pretty, golden ‘citrine’ that can cut brilliant yellow stones. Or glowing, dark purple amethyst with seductive blue flashes, dreamy rose quartz, or rutilated quartz with geom...

By Peter Rosewarne

   

Having built-up a mineral collection the question arises, at some stage, as to what to do with it looking to the future. Options include do nothing (and continue to get enjoyment out of looking at and handling the specimens) and let someone else worry about it when you’re gone (i.e. throw it away), give it away, donate it to an institution (probably unwise in SA or anywhere probably), or sell it. This article looks at some aspects of the pricing and selling process ba...

By Duncan Miller

Topaz is a rather under-rated gemstone. This perhaps it due to the fact that pure, colourless topaz is relatively plentiful. Much of it is irradiated and then heat-treated to produce various intensities of bright blue. Natural blue topaz tends to be much paler, although dark blue stones do occur naturally. These are rare and hence more valuable. Natural topaz occurs in a wide variety of colours, including light green, yellow, orange and pink. The famous orangey-pink topaz fr...

Talking about treasure hunting, let me tell you my story … It’s a tale of two parts.

I’ve always been the poster child for the story told by Victor Borge:  “if there’s manure, there must be a pony.”  It’s in my DNA.

Truth be told, my first real life encounter with this approach was doomed. 

To understand it better, you’d have to know that back then Dinner, Bed and Breakfast at a swanky hotel cost R40-00 and a full seafood buffet at the same hotel with all you could eat cos...

By Duncan Miller

I started faceting in pre-GemCad days and found cutting ovals very laborious. I would cut the girdles by eye, using various oval templates, and placed the brilliant-style facets by eye too. Producing matching pairs was very trying. The advent of meetpoint faceting and GemCad overcame all these difficulties. Now there are lots of designs for ovals that are meetpoint, requiring no preform, with the girdle outline evolving out of the cutting sequence. You can access some of the...

The Waldorf School asked us if they could visit the club again this year, and Claire Vaskys organised the day for them. Thank you very much Claire.

Also a big thank you to Rinda who had kept all the little offcuts of stones, and dopped them in preparation for the children to grind and polish, and who managed the workshop while they were busy between machines. 

Thank you to Marsiglio who brought his tools, raw and finished materials, and allowed the kids to take his rock pick and smash it in...

By Duncan Miller

This was another jeweller’s request. The setter had broken one of a matching pair of blue-green stones, destined for earrings, bought by the client in India as emeralds. They were apatite; but nevertheless the broken stone had to be replaced to fit the already-made setting. Fortunately I had just one piece of blue-green apatite that matched the colour. In order to produce a stone of the same size and proportion I had to replicate the oval precisely. I could have slapped fa...

Verdite

Verdite is a fairly soft South African stone found in the Barberton area. It is often seen in African curio shops carved into animals. Its golden flecks distinguish it from buddstone which is a much harder metamorphosed chert. Even more distinctive is the “leopard rock” which is spotted serpentinite, also from that area. JW

 

Buddstone

Leopard rock

 

By Duncan Miller

Here is a quick and easy oval with a standard 1:1.30 proportion. It has a fully conical pavilion, so you can spin a conical preform, stopping just short of producing a point. This means you don’t have to change angles and mast height when cutting the sixteen pavilion facets, which saves time and avoids mistakes. This is a fully meet-point design that doesn’t require a preform, so it would be good for a beginner’s first oval. It doesn’t work well in quartz or beryl, s...

Jako Schonken

I arrived at OR Tambo airport on a cold winter’s Thursday morning, hoping it wouldn’t rain. I hired a car and started driving in a northerly direction, following my GPS to Marble Hall - a place I have only heard about in the South African Micromount Society’s newsletters. I have been a member of the South African Micromount Society (SAMS) for more than three years, but have never been to their meetings or outings since they are based in Gauteng. Nor have I ever met any of...

By Duncan Miller

Matt Lurie (5 years old), who lives in Johannesburg, was curious as to the make-up of an (amethyst) Spirit quartz crystal so he bought one for R10 in Johannesburg and de-jacketed/exfoliated/peeled it, to satisfy his curiosity! The images below were taken by his dad (Robert’s son) Dan Lurie.

   

Built in 1923 the old silos in Cape Town Harbour were used for storing grain awaiting export, and were in operation until 1995. Today they house a modern art gallery. Thanks to the generous sponsorship of Jochen Zeitz, (former CEO of Puma) and the incredible architectural imagination of the Heatherwick Design Studio, the building is now a magnificent place to visit. The old round tubes of silo have been cut away in specific places to open up a central ...

Here are two stones that Duncan Miller cut recently from rough he bought two months ago at Open Day. The yellow citrine (from Johann de Jongh) has only 58 facets, is 22 mm wide and weighs 37 ct. The design is ‘Xephyr’ by Arya Akhavan (yes, with an ‘X’). The light green fluorite (rough from Rob Smith), is the first one he has ever cut. It has even fewer facets, only 36, is 15,5 mm wide and weighs 16,2 ct. The design is slightly modified from ‘Six Shooter’ by the late Jeff Graham.  ...

 A magnificent 63 carat sphalerite from Aliva in Spain (http://gem-sphalerite.com/) cut by Duncan Miller. The design is Marco Voltolini’s “Superstarfish Dome 80”.

 A unique type of blue-green garnet has entered the gem market. The garnets reportedly come from a deposit near the border of Tanzania and Kenya. GIA’s Carlsbad laboratory obtained a small parcel of blue-green rough material and two faceted stones for examination. Unlike traditional blue-green garnets that exhibit a colo...

The word “tripping” can have two meanings:  a tour or journey, or an unintentional slip, blunder or happening.  On this occasion both senses of the word applied. Malcolm and his friends covered a lot of ground and saw a wide variety of things when in Namibia, but not without incident.

To start off with, by the time Australian Graham landed in Cape Town, he had lost his passport, which necessitated a return to Johannesburg and the Australian Consulate for a new one. He then flew from JHB...

“Eye of the Storm” a faceting design created by Robert W. Strickland on 12^th September 2017, in honour of those who suffered loss in the Caribbean hurricanes of 2017.

This design was first published in the United States Faceters’ Guild newsletter of September 2017.

When photographed directly into the centre of the culet, all the crown facets go dark, and the only light is in the “eye”, but viewed from other angles, the stone ...

Duncan Miller

A polariscope consists essentially of two polaroid filters, or a source of plane polarised light and one polaroid filter. The source of polarised light can be a white computer screen or even the sky, viewed at 90 degrees to the Sun. For the filter, or analyser, you can use a sheet of polaroid, or a lens from a cheap pair of 3D movie spectacles.

Let’s start with a white computer flat screen. Even an older cell phone screen without a plastic cover produces plane polarised ligh...

About ten intrepid Jan Coetzee crystals made it to the reunion, with two of 50 kg-plus guys sending their apologies due to being overweight, along with a couple more whose owner couldn’t provide transport on the day. One rare and seldom seen fluorite (also from the same crystal pocket) came, and was much admired. Malcolm Jackson gave a short presentation about the mine and its location, along with photos taken by him and Jo of the Jan Coetzee mine dumps in recent years and the remains of th...

Duncan Miller

During the 1974/75 university holidays I was fortunate to work for Sid Pieters in Windhoek for several months. It was a wonderful experience, including seeing some of the most famous mineral specimens then coming out of Tsumeb, but also to encounter some very special gem materials. Through Sid Pieters’s generosity I returned home to Cape Town with a few small fragments of jeremejevite from the original Namibian occurrence at Cape Cross and some pieces of cuprite from Onganja t...

Lesley Andrews gave a most interesting talk on Scottish curling stones. I thought curling was a Scottish winter game played by village yokels. I was wrong! It has had Winter Olympic status since 1998. The game consists of two teams of four players each, with eight stones between them, and the idea is to slide the stone, which turns, hence the name curling, towards a target called a button. Rather like a game of bowls on ice. The origin of the game goes back into obscurity, but the oldest know...

Duncan Miller

Inclusions in gemstones often are seen as just a nuisance by faceters, who find themselves urged to buy only ‘clean’ rough. I suppose it is a matter of taste, but inclusions that do not detract from the visual appearance of a gemstone can aid in proving its authenticity. And some inclusions definitely enhance the value and appearance of certain gems. A visible ‘horse tail’ inclusion of asbestos fibres in Russian demantoid is perhaps the most famous example of desirable ...

Duncan Miller

Synthetics are a wonderful source of relatively inexpensive faceting rough, in a wide array of colours, some of them not available at all in natural stones. On the whole, synthetic gem rough is predictable in its behaviour and also enables the cutter to explore quirky cuts in larger sizes than would be affordable in natural rough. And increasingly jewellers are setting well-cut synthetics in precious metal jewellery. So dive in, and enjoy yourself.

The most commonly available ...

Transparent to whitish barite mineralization was found in an orogenic late phase leached fault zone. It seems that some of the barites are pseudomorphs replaced by snow white baritocalcite. This replacement supposedly took place at an even later phase when calcium-rich fluids migrated through the formation. This theory is supported by the occurrence of floater quartz crystals in a pocket where, on the one side, the quartz aggregates display the luster of ‘bergkristall’ and are coated on t...

Duncan Miller

Author: Gisela Hinder, Rosh Pinah Geo Center, Rosh Pinah, Namibia

e-mail: gisela.hinder007@gmail.com

 Rosh Pinah Mine is situated in the southwest of Namibia about 80 km east of Oranjemund. Rosh Pinah Mine became well known for its beautiful barites when a massive pocket of yellow to orange barite crystals was opened in 1989. It is said that these barites were the best ever found in Namibia.

In February 2017 new barite crystals were discovered at Rosh Pinah. Yellowish, unfortunately smallish, ...

Duncan Miller

Garnets are among the easiest gem materials to facet. They have no distinct cleavage, although some crystals have a parting that causes them to fracture into thin slabs. The rough often is in globular shapes, which is good for weight recovery. When choosing rough, avoid being fooled by fake material. Red glass is sometimes covered in adhering deceptive ‘grit’ to mimic natural nodules. Illuminated from behind or the side with a torch, the characteristic internal swirls and r...

Jo Wicht

Blue Lace “Agate” is found on the farm Ysterputs 254 (meaning iron holes) in Namibia. The mine is located adjacent to the “Blinkpan” (shining shallow lake) which can be seen to the west of the B1 highway about 80 km north of Vioolsdrift and Noordoewer, which are the border towns on either side of the Orange River between South African and Namibia.

Blue lace is not a true agate, but a chalcedony (microcrystalline quartz) laid down in a series of wavy bands, which gives it th...

Duncan Miller

Many faceters recommend that beginners start with aquamarine. It usually presents no problems in faceting or polishing, is relatively easy to obtain, and in lighter colour it is not overwhelmingly expensive. Aquamarine is the blue or blue-green gem variety of the mineral beryl, an aluminium beryllium silicate. It occurs in elongated hexagonal barrel-shaped crystals. It is dichroic, with the most intense colour when viewed along the length, the so-called c-axis. This is a pity, ...

Duncan Miller

This is the first of an intended series of articles on faceting and polishing a variety of gemstones. I am beginning with quartz because that is what most people start faceting when they first take up the hobby. Quartz rough is inexpensive and readily available in a wide range of colours. It is not necessarily the easiest material to polish, but if a particular stone behaves badly it is no great loss to set it aside to be tackled at a later date. You should try to select rough ...

I cut off the end of a damaged Goboboseb quartz crystal because it had a deep purple central inclusion at the one end, which I thought would make an interesting stone to facet.

 But then I noticed that the end of the remaining piece had regular purple stripes radiating from the centre to the points of the hexagonal crystal. So I cut off another section of the crystal to the depth I hoped I would need for cutting a gem.

I first tried to find the middle of the purple star shape, and marked s...

Not many people in our club know Nigel Brown, but behind the scenes he must be one of our most productive lapidaries, in and among all his other commitments. His website has been listed in this newsletter’s advertisements for several months now (nigelbrownjadecarver.com). When I looked at it again recently I saw he had been busy producing jade kiwis so I asked him for an update of his work. He sent us this: 

“Little Spotted Kiwi

This little...

In the bad old days, one cut facets on a 600 mesh lap, followed by a 1200 mesh lap and then went on to polish. The 1200 mesh leaves quite deep scratches, and on some material produces ‘orange peel’, a mottled surface with alternating rough and smooth patches. This makes polishing tedious. A pre-polishing step, with 3000 mesh or 8000 mesh diamond gets rid of the scratches and any orange peel. You might think the additional step adds time to the process, but in practice it speeds it up beca...

By Duncan Miller

If you are going to facet, you need to learn something about mineralogy because you need to know what stones you should obtain, how their characteristics affect their behaviour while you are cutting and polishing them, and how they affect the optical properties of your finished gemstone. The easiest material for beginners to cut and polish is common red garnet. It presents no problem with cleavage or orientation for colour, and generally behaves itself well during ‘cutting...

By Gisela Hinder, Rosh Pinah Geo Centre

Reproduced with the permission of Eric Greene of Treasure Mountain Mining

Azurite is a soft, deep blue copper mineral produced by the oxidation weathering of copper ore deposits. It is a favourite amongst mineral collectors because of its rich blue colour and wide availability in a variety of forms and colour variations, from sharp, lustrous brilliant dark blue crystals to thick, rich, colourful royal blue coatings on matrix.

Azurite suns are a unique form of azurite that has been found in ...

A couple of years ago, I bought a small ornamental gold-panning miner from a charity shop. As he was related to our hobby, I wanted to rescue him from an unknown fate, and little did I know it then, but he was the start of a new collecting hobby. Today, I have several mining ornaments, which were shown at a “What’s Up?” exhibit at the June monthly meeting. They are rather rare, and all have been bought cheaply from secondhand dealers. They are made of metal, with two mounted on sliced a...

by Martine van der Westhuyzen

In the FOSAGAMS announcement of their coming Vivo outing in July, I read that, amongst other stones, dragon stone can be found at Vivo. I wondered what dragon stone could be, so I consulted our old friend Google to find out. This yielded such a diverse set of responses that it took me several hours to try to get to the bottom of the mystery. It included references to dragon stone, dragon blood stone, bloodstone, etc. – but are these all different kinds of stones...

 “The Romance of the Stone?!”

-        excitement at having found a special piece of rough that asks for faceting

-        carefulness to get the right design for the rough

-        caution by previewing the new design on GemCad first

-        fear to start new designs or try different types of stones

-        bravery to just do it

-        patience to remove the initial surplus rough and reach the centre point and s...

Then Richard Harrison gave a talk on Tsumeb minerals. He recently graduated with a degree in geology, and we are proud of our new whizz-kid. H...

If you remember, last November, TVJ (with the aid of Malcolm and his photos) gave us a very interesting talk on zeolite minerals. These minerals are to be found in ancient lavas that flowed out millions of years ago from volcanoes such as those at the Etendeka Plateau in Namibia or the Deccan Trappes in India. Later such minerals as analcime, chabazite, heulandite, and apophyllite were created by mineral rich solutions percolating through the porous rock and filling the residual cavities, k...

André Bergh gave a talk and demonstration of what were described in the last newsletter as “quartz singing bowls”. But as things turned out, the bowls were made of frosted glass, in China. There was a selection in various sizes, and they are tuned to musical notes. When tapped with a drumstick, or using one in a stirring motion rubbing against...

Dave Hawes

I have always thought that there are two types of people in the world, those who collect and those who don’t.

Those who don’t, often live in immaculate, almost antiseptic, homes where nothing is out of place.

Those who collect can be divided into several groups: Those who collect for business or academic reasons, it is their work. Those who collect for the appreciation of all things natural, and who usually display a few prized pieces on their mantelpiece. Those who collec...

Rockey Ollewagen

My interest in crystals started about fifteen years ago. I was just a regular IT guy, working in the corporate environment, not having any idea what the crystal world was all about.

Then my wife, Paula, arrived home one day with a quartz crystal which cost R70 at the time. I couldn’...

Graham Harrison

The whole thing started with a chance find of some lovely smoky quartz crystals while on holiday in the Knysna area in 1973. I did however grow up on a farm near Johannesburg, so these smoky quartz crystals led to me hunting for amethyst in the Muldersdrift area and in later years spending many days at the old limestone quarry outs...

From the International Gem Society Reference Library

Introduction
... Lapidary is a hobby that is enjoyed by people of all ages and circumstances. Unlike most hobbies, what you produce is actually worth more than the labour you put into it. For many cutters, their hobby becomes a part time, or full time profession. 
... Gem cutting can be don...

The rocks in the hyper-saline waters of Lake Thetis, about 120 km north of Perth in Western Australia, are not quite what they seem. They are actually living things. Stromatolites are the oldest living life-forms on our planet.

There are some mineral specimens in this world that beggar belief and the opal pineapples from White Cliffs in Australia are amongst those. They are palm-sized clusters of radiating points, looking like some bizarre fruit and have been known since the beginning of the 20^th century. Found only in the Cretaceous sediments of the White Cliffs opal field in New South Wales, they occurred in an area which has also produced opalised fossils of marine shells, pieces of wood, and even the occasional ...

Pegmatites are dike-like bodies of large grained igneous rock, formed by the slow crystallization of highly volatile solutions, during the last phase of solidifying deep-seated granite magmas. The name comes from the Greek word “pegmos” meaning “coarse”, and refers to their large-sized crystals, which are mainly feldspar, quartz and mica.  Their origin begins when a huge mass of molten magma intrudes upwards through cooler surrounding country rock, a name given to all other rocks, whi...

One of the least known quarries of the Cape Peninsula, and not easy to spot, was worked on Seaforth beach in 1865, where granite was shaped on site to re-enforce the shaky foundation of Roman Rock lighthouse, built only a few years earlier in 1861.  This well known False Bay “landmark” (if one may call it that) is South Africa’s only lighthouse built on a rock at sea, which becomes visible at low tides.  It was quite an achievement to...