mineral

Quartz with Arsenopyrite

Silicon Dioxide (SiO2) with Iron Arsenic Sulfide (FeAsS)

Quartz: Hardness 7, Transparent/White, Vitreous luster, Trigonal system. Arsenopyrite: Hardness 5.5-6, Metallic luster, Steel-gray color, Monoclinic/Triclinic system, brittle.

Identified March 20, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Quartz: Hardness 7, Transparent/White, Vitreous luster, Trigonal system. Arsenopyrite: Hardness 5.5-6, Metallic luster, Steel-gray color, Monoclinic/Triclinic system, brittle.

Formation & geological history

Formed in high-temperature hydrothermal veins and pegmatites. These minerals often precipitate together from mineral-rich fluids escaping from cooling magma; they vary in age from millions to billions of years depending on the deposit location.

Uses & applications

Aesthetics and mineral collecting. Quartz is used in electronics and glass; Arsenopyrite is the primary ore of arsenic used in pesticides and wood preservatives.

Geological facts

Arsenopyrite is often called 'Mispickel'; it gives off a distinct garlic odor when crushed or heated due to its arsenic content. This combination specimen is highly sought after by collectors for its contrast.

Field identification & locations

Identify by quartz crystal habit (hexagonal prisms) and the metallic, striated gray crystals of arsenopyrite. Common in Panasqueira (Portugal) and Yaogangxian (China). Use caution when handling: wash hands after touching to avoid arsenic residue.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral

Epidote

Epidote - Ca2(Al2,Fe3+)3(SiO4)3(OH)

mineral