Malachite ps. After Gypsum (old classic) Kay Robertson Coll.

Item Description

A classic, excellent and rare old-time epimorph (type of pseudomorph) from this well-known Utah locale. Nubby banded malachite has replaced a gypsum crystal and the original gypsum dissolves away, leaving a sharp hollow cast surrounded by the new mineral. The Apex Mine is well-known for this material, but it is very seldom available and only out of old collections. Older material from the 1950s or early 1960s. Comes with old 8.3 cm lightweight triangular wood display label. Ex Kay Robertson Collection # 2991 and purchased from Bob Dye at the San Jose Show in 1963. Kay is a prominent California collector, who specialized in European classics (see the article in the March-April, 2007 Mineralogical Record). Valued at $900-1000.