3.32 ct GYPSUM – CHINA

Gypsum
After cutting some of the most insane rough materials—stones that are water-soluble, poisonous, or even radioactive—some of my gemologist friends and fellow cutters started mocking me. They asked what I could possibly take on next, joking about whether I planned to cut gemstones with my fingernails. They suggested talcum powder or maybe Gypsum, both materials with such extremely low hardness that the idea of faceting them seems like a fool’s errand. Well, we did it. We successfully faceted Gypsum, and we even cut Talcum. Neither material was enhanced or treated in any way; we simply mastered the pressure required to shape them. You can call us insane, but the results speak for themselves.

The Heritage & Discovery

Historical Significance: Gypsum is one of the most widely used minerals in human history, but rarely in the context of jewelry. From the alabaster carvings of Ancient Egypt to the plaster used in the Renaissance, it has always been a structural or artistic medium. In the world of rare gemstones, however, a faceted Gypsum is the ultimate testament to a lapidary’s skill, representing the ability to stabilize and polish a mineral that most people can scratch with a thumb.

Discovery: Known since antiquity, the name Gypsum is derived from the Greek word “gypsos,” meaning plaster. It was first described in a modern mineralogical sense by various early naturalists, but its chemical identity as a hydrous calcium sulfate was solidified as the field of chemistry evolved. It remains a foundational mineral in the study of evaporite deposits.

Important Mines: While Gypsum is found globally, the most legendary source for massive, transparent crystals is the Naica Mine in Chihuahua, Mexico, home to the famous “Cave of the Crystals.” For facet-grade rough that is clean enough for our work, we often look to the deposits in Utah, USA, or the fine specimens from Italy and Morocco, where the “Selenite” variety produces the water-clear transparency we require.

Mineralogical Profile

Description: Gypsum is a very soft sulfate mineral composed of calcium sulfate dihydrate. It crystallizes in the monoclinic system and is the defining mineral for a 2 on the Mohs scale. It features a vitreous to pearly luster and perfect cleavage in one direction, which makes faceting an exercise in extreme caution. Because it is so soft, achieving a high polish without “bruising” or rounding the facet junctions is the greatest challenge we face when working this material.

Chemical Formula: CaSO₄·2H₂O