Black tetrahedral crystals of sphalerite up to 8 mm in size across this matrix (4.5 × 3.0 × 2.0 cm) with chalcopyrite and calcite. Found from Creede, Mineral Co — Photo: Ivar Leidus · CC BY-SA 4.0
Sphalerite
Also known as: Zinc blende, Blende, Black-jack, Ruby blende.
Zinc sulfide — the world's main zinc ore — black to honey-yellow crystals with remarkable adamantine luster.
Intro adapted from Wikipedia (CC BY-SA).
Sphalerite is an IMA-recognized mineral species in the sulfide class, with the chemical formula ZnS.
It crystallizes in the cubic crystal system (space group F-43m). It is a member of the Sphalerite structural group.
Key properties: Mohs hardness 3.5–4; specific gravity 3.9–4.1; typically brown or black or yellow or red or green or colorless; Pale brown to pale yellow and white streak; Resinous to adamantine luster.
IMA symbol Sp, IMA status: approved, named in 1847.
Formed under a wide range of low- to high-temperature hydrothermal conditions; in coal, limestone, and other sedimentary deposits.
It is found associated with Galena, chalcopyrite, marcasite, pyrite, fluorite, barite, quartz, many other hydrothermal minerals.
Its name comes from the Greek for treacherous, the mineral sometimes being mistaken for galena, but yielding no lead.
Collections: Metals & Native Elements, Collector Favorites, Fluorescent & Glowing.