Unearthed Gemstones Jewelry Catalogue

Hypersthene

A dark pyroxene mineral with a silvery, satin-like flash
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Raw stone of Hypersthene
Hardness
5.5 - 6 (Medium): Wear with care; This gemstone can dull over time.
Toughness
Fair (Needs care — Vulnerable to knocks and sharp blows)
Mineral Family
Pyroxene (Enstatite-Ferrosilite)
Transparency
Opaque
Crystal System
Orthorhombic
Lustre
Submetallic

Hypersthene is an iron-rich orthopyroxene, closely related to bronzite, with a look all of its own. Polished stones are deep charcoal to black with a silvery, satin-like flash that sweeps across the surface, an effect caused by light reflecting off fine internal plates. Some pieces shimmer almost like dark labradorite. Notable sources include Canada (especially Quebec and Labrador), Greenland, India and the USA. The name means over strength in Greek, coined because it is harder than the mineral it was first confused with.

Despite that confident name, hypersthene sits at 5.5 to 6 on the Mohs scale and has pyroxene cleavage, so treat it gently. It is cut as cabochons to catch the silver sheen, and it is stunning in pendants, earrings and occasional-wear rings, particularly in darker, modern designs. Store it away from harder stones and clean it with warm, soapy water and a soft cloth. It remains a collector's favourite precisely because you do not see it everywhere.