Miargyrite is a mineral, a sulfide and antimony 2. It is a dimorph. Originally discovered in the Freiberg in 1824, it has subsequently been found in many places where silver is mined. It usually occurs in low temperature hydrothermal deposits. and forms black metallic crystals which may show a dark red internal reflection. The streak is also red.
Miargyrite is named from the Greek meyon, "smaller" and argyros, "silver," as its silver content is lower than most silver sulfides.