Geological Tour of the Rosh Pinah area

September 25, 2018
Since we have never fully explored the southern parts of Namibia before, we decided to head up to Namibia a few days before the planned start of the FOSAGAMS Namibia 2018 tour to explore the area. Heidi Naudé from the Pretoria Club put us in touch with Gisela Hinder who owns the Rosh Pinah Geo Center and after some discussion with Gisela on our interests, we pre-booked a guided geology tour with her. Our first night in Namibia was spent camping along the Orange River, and a casual walk across the road resulted in us loading our pockets with some particularly colourful tumbled banded-ironstone pebbles. 


Naturally tumbled banded ironstone pebbles

On arrival in Rosh Pinah, we immediately fell in love with the aesthetic design of the Geo Center which incorporates natural local material and blends in so well with the area. A pretty thatched roof and stone walls complement the airy, large windows of the museum section. And inside, in custom-built cabinets, is a plethora of old Rosh Pinah and Skorpion Mine lead and zinc specimens to appreciate, as well as excellent specimens from the greater Namibia area on display.

Before heading out on our field trip, Gisela provided us with a thorough overview of the geology of the area, information on the mining techniques and history of Rosh Pinah and some insight into her background as former geologist for the Rosh Pinah mine. And soon we were heading out along the newly graded C13 River Road to visit the first of the abandoned alluvial diamond mines.


The Rosh Pinah Geo Center


Schorl on feldspar, Erongo. (40x34x24 cm?)  Large specimen


Large specimen of Orange River quartz (24x21x15 cm)


Rare skorpionite on tarbuttite from the skorpion mine,
and other specimens on display


Large specimen of smoky quartz and fluorite from the
Erongo area (56x42x24 cm)

Along the way, we stopped at a very interesting road cutting at the ‘dropstone’ deposit, where there was clear evidence of major geomorphological changes to the rocks and substrates of the area, no doubt contributing millions of years ago to the formation of such a rich and diverse variety of minerals found in the area today. Here we saw striations in the rock face, bands of conglomerate rock which under tremendous pressure at some point in the history of earth buckled and bent into sweeping waves of layered rock, massive brooding solitary boulders eroded from the softer surrounding material which have been the centre of dissension amongst the experts as to whether they could have been carried into the area as part of glacial deposits.


About to enter the old diggings

As we tumbled out the vehicle at the first alluvial diamond site, we hardly stopped to appreciate the view, as our eyes were already turning and tuning into the abandoned diggings in the naive hope that we would stumble across “one” waiting all these years for us to arrive. Of course, our minds knew better, and it was still very interesting to dig against the wall of the pit for other material which duly revealed itself, such as agate, carnelian and exquisitely fragile more recently grown gypsum crystals.

Our next stop took us to the historic Lorelei Copper Mine where we spent a fair amount of time wandering through the deserted buildings, absorbing the nostalgic essence of the site, letting our imagination roll back the years to the sweat, manual labour and extreme exertion that the old miners endured. We marvelled at the tenacity of the old timers and the enormity of the challenges they faced and overcame. The mine tunnel itself has been filled up for safety reasons, but there is still evidence of the workings and the old track which used to ferry the rocks from the mine to the leeching dams.


Gisela explains how the copper is extracted


Len examines a copper-bearing rock outside the filled-up adit of the mine


The old leeching dams

After a quick stop to search for Orange River Quartz at one of the quartz outcrops, we headed down to see the historic Sendelingsdrift Pontoon which has been in operation for 43 years; a curious but novel border post into Namibia. The peaceful scene of the pont waiting sedately to ferry cars across the Orange River belies a bit of a chequered history of smugglers and black market traders, disastrous crossings resulting in a watery grave for many vehicles, and several wash-aways during the 1980s and as recently as 1998 when a flood took the pont exploring further down the canyon. Thankfully the current-day design and operation seems reliable enough with a newly designed shallow draft vessel capable of carrying 6 metric tonnes.


The pontoon waits on the South African side of the Border to ferry vehicles across the Orange River

Having Gisela on board from a geology perspective and pointing out fascinating rock formations and how they came about, made all the difference between just appreciating the landscape and an actual learning experience. While having a wealth of knowledge about the area, Gisela hasn’t lost her sense of fun and adventure, making the trip thoroughly enjoyable with ample time spent on the dig.

 

FaceTips for October

September 25, 2018

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...


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Southern African Lapidary Stones to watch out for

September 25, 2018

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

 

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FaceTips for September

August 24, 2018

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...


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STAVOREN MICROMOUNT OUTING

August 24, 2018

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...


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FaceTips for August

July 25, 2018

By Duncan Miller

Jewellers sometimes ask for the impossible, and it’s a challenge to try and oblige. This design was developed to cut the citrine for a dome-shaped ring. It had to be a ‘classical’ mixed cut with curved girdle lines to match the curve of the top of the ring. This design requires a preform to get the girdle facets the right size. The relative depth of the pavilion tiers affects the angles of the triangular corner facets, but these can b...


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Southern African Lapidary Stones to watch out for:

July 25, 2018


SODALITE – this is generally sourced from Swartbooisdrif, near the Kunene River in north-west Namibia. It has a Mohs hardness of between 5,5–6, is generally fine grained, and works very well.

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Encouraging the Curiosity of the Next Generation

July 25, 2018

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.

   


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Zeitz Museum of Contemporary African Art

May 24, 2018
Once the grain silos of Cape Town Harbour

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 ...


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Faceting

May 7, 2018

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.  ...


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