Browsing Archive: May, 2019

FACETIPS A simple Emerald Cut

Posted by Site Moderator Webmaster on Thursday, May 9, 2019, In : Faceting 

Duncan Miller

The Emerald Cut is not a meetpoint design so cutting stones with repeatable proportions and facet widths involves guesswork. The following sequence for cutting pavilion and crown avoids most of the guesswork and enables you to cut pairs or sets of matched stones. This sequence is modified from FACET DESIGN Vol. 4 by Robert Long & Norman Steel, in turn based partly on FACETING FOR AMATEURS by Glenn & Martha Vargas. This example uses 5° steps for the three pavilion tiers, but you ...


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WHAT IS A PSEUDOMORPH, AN EPIMORPH OR A PARAMORPH?

Posted by Site Moderator Webmaster on Thursday, May 9, 2019,

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.

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


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Phlogging a dead horse?

Posted by Site Moderator Webmaster on Thursday, May 9, 2019, In : Mineralogy 
Jo Wicht

Many of you are aware of my obsession with Blue Lace Agate, both from a lapidary point of view and with stones from the mine, as well as my curiosity as to how the mineral was possibly formed. Any new information that I come across, be it a new specimen or comment, has to be investigated. Recently it was Marco Campos-Venuti’s new book (Banded Agates: a genetic approach (2018) www.agatesandjaspers.com) which set me off on the trail again because it has a chapter on Lace Agates. Marco...


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