Pink Diaspore

Posted on May 1, 2021 by John J. Bradshaw, GIA GG

INTRODUCTION In the July/August 2019, Volume 38, Issue 4, Gem Note, I wrote about diaspore from Turkey that for all intents and purposes was a single-source gem. Although a small amount of gem material was found in Burma, it certainly was not in commercial quantities. During February of 2020, a new source of pink diaspore was found near the village of Ragha in the Goshta District of Nangarhar Province, Afghanistan. At the time of writing, it is not known how much production this new deposit will yield, but multiple kilograms of rough material have been processed through-out 2020 and the early part of 2021. COLOR Turkish diaspore has a distinct color change. The change is more subtle in some stones. Generally, the larger the stone, the more dramatic the change. The daylight color is a yellow-green while the incandescent color is a champagne to yellow-brown. The new diaspore from Afghanistan does not appear to have a strong color change. In daylight, the color is a purplish-pink (Figure 1) while in incandescent, it is more pink without the purple modifier. The direction of best color is looking down the b-axis. Perpendicular to the b-axis is the direction of perfect cleavage so careful orientation must be done during cutting to give the best face-up color while being mindful of the easily opened cleavage. FIGURE 1. Pink Diaspore, 5.40 ct, from the new find in Nangarhar Province, Afghanistan. Photo by John Bradshaw (www.rarestone.com). CLARITY Much of the pink diaspore rough seen to date has areas capable of cutting medium to large size stones that are eye clean and in many cases loupe clean (Figure 2). Similar to the Turkish material, cutting can prove to be difficult due to the perfect cleavage on the {010} face. Polishing is much easier than the faceting process with stones taking a high polish. STONE SIZES Thus far, it appears the Afghan pink diaspore can be cut into sizable stones. To date, large fine stones between 40-60 ct have been fashioned. At the time of writing, I have seen rough that could possibly produce stones approaching 100 ct. Proper orientation of the rough during cutting allows...

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