Arsenopyrite

FeAsS

The image displays a silvery-white to steel-gray metallic mineral, likely arsenopyrite, exhibiting a crystalline habit, possibly prismatic or tabular, with a pen providing scale.

Arsenopyrite Physical Properties

Mohs Hardness

5.5

Crystal System

monoclinic

Luster

metallic

Streak Color

dark grayish-black

Cleavage

distinct on {101}

Fracture

uneven to conchoidal

Specific Gravity

Colors

silvery white, steel gray

Transparency

opaque

Type Locality

Worldwide, notable localities include Freiberg (Germany), Cornwall (England), various gold districts in Canada and the USA.

Mineral Group

Sulfides

Uses

ore of arsenic, minor ore of gold, collector specimens

Associated Minerals

gold, pyrite, chalcopyrite, sphalerite, galena, quartz, tourmaline

Rarity

common

Geological Context

Arsenopyrite commonly forms in high-temperature hydrothermal veins, contact metamorphic deposits, and pegmatites, often serving as an indicator mineral for gold deposits.

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Related Specimens

Diopside

Brookite

Ferberite

Milky Quartz

Almandine

Actinolite