sphalerite (redirected from Black-jack ore)

sphalerite (sfăl`ərīt, sfā`–), mineral composed of zinc sulfide, usually containing some iron and a little cadmium. It occurs in crystals of the isometric system but more generally in cleavable, compact masses. It is transparent to translucent and varies greatly in color, iron-free specimens being pale yellow and those with iron being brown, red, black, or green. The most important source of zinc, sphalerite is a widely distributed mineral that commonly occurs in association with galena. It is found in large deposits in many parts of the world.

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sphalerite

 or blende or zincblende

Sphalerite from Baxter Springs, Kan.

(credit: Courtesy of the Ted and Elsie Boente Collection; photograph, John H. Gerard—EB Inc.)

Zinc sulfide (ZnS), the chief ore mineral of zinc. It is found associated with galena in most important lead-zinc deposits. The most important deposits are in the Mississippi River valley (U.S.), Poland, Belgium, and North Africa. See also sulfide mineral.

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sphalerite [′sfal·ə‚rīt]

(mineralogy)

(Zn,Fe)S The low-temperature form and common polymorph of zinc sulfide; a usually brown or black mineral that crystallizes in the hextetrahedral class of the isometric system, occurs most commonly in coarse to fine, granular, cleanable masses, has resinous luster, hardness of 3.5 on Mohs scale, and specific gravity of 4.1. Also known as blende; false galena; jack; lead marcasite; mock lead; mock ore; pseudogalena; steel jack.