Ammonium nickel sulfate (synthetic) (imitating Dioptase)

Item Description

A rarely seen specimen of crystallized ammonium nickel sulfate (sometimes nickel ammonium sulfate) grown in a lab in Germany years ago. Jack didn't really have much in the way of synthetic material in his collection, but color and aesthetics count, and he referred to this piece as a "Dioptase" due to the semi-trigonal shape of the crystals (they're actually monoclinic) and the rich color. I will say that Dioptase is a bit more green than these ammonium nickel sulfate crystals, but at a distance, you can clearly see the resemblance between this piece and a Tsumeb Dioptase. The crystals measure up to 4.0 cm, and were grown on a natural matrix (possibly a piece of rock from Tsumeb?) and are in fine condition, though I can see one ding, so it's not completely pristine. A cool old-time synthetic specimen that dates back at least a few decades as the old Ken Roberts label mentions it was grown in West Germany, so it predates the fall of the Berlin Wall.
From the collection of Jack Halpern No. 2172. Jack was born May 18, 1920 in Brooklyn, New York, but has been a long-time resident of San Francisco. He assembled one of the great mineral collections in the world encompassing over 3,200 specimens with a specific emphasis on color, quality, and style/aesthetics, which is evident in every piece. He admired specimens of all sizes from thumbnails to large cabinets and the vast majority of them rank from fine to world-class in their quality.
Above all else, Jack is considered to be the greatest gentleman in the modern era of mineral collecting. He is beloved by all those who have met him, and he truly is one of the most iconic figures in the mineral world. We recently acquired Jack's collection, and the VAST majority of these pieces will be offered here in the auctions, as we feel that everyone deserves and equal opportunity at acquiring these important, well-documented and fine quality pieces for their collections. We are honored to have the opportunity to offer Jack's treasures to everyone on a regular basis in the auctions.
We encourage you to read our blog post at https://www.irocks.com/the-jack-halpern-collection or his profile on the Mineralogical Record website https://mineralogicalrecord.com/biographies_labels/halpernjack/ for more information