Pyrargyrite

It's advisable to handle pyrargyrite carefully to avoid generating dust and wash hands thoroughly afterward. When cutting or polishing pyrargyrite, wear a dust mask to prevent inhaling heavy metal particles. Store pyrargyrite in a sealed container in a well-ventilated area, away from children and pets. For those involved in crystal healing, never put it in your mouth.

The Mohs hardness is 2.75, and the specific gravity 5.85. The refractive indices (nω=3.084 nε=2.881) and birefringence (δ=0.203) are very high. There is no very distinct cleavage and the fracture is conchoidal. The mineral occurs in metalliferous veins with calcite, argentiferous galena, native silver, native arsenic, &c.

Pyrargyrite is typically mined as a source of silver, which it often thought of as a precious metal used in jewelry and decorations. However, silver mined from pyrargyrite has many other uses, ranging from metal alloys used in dentistry to batteries. Silver is also used in tips of gloves that are touchscreen-sensitive.

The best crystallized specimens are from Sankt Andreasberg in the Harz, Freiberg in Saxony, and Guanajuato in Mexico. It is not uncommon in many silver mines in the United States, but rarely as distinct crystals; and it has been found in some Cornish mines.

The color of pyrargyrite is usually greyish-black and the lustre metallic-adamantine; large crystals are opaque, but small ones and thin splinters are deep ruby-red by transmitted light, hence the name, from the Greek pyr and argyros, "fire-silver" in allusion to color and silver content, given by E. F. Glocker in 1831. The streak is purplish-red, thus differing markedly from the scarlet streak of proustite and affording a ready means of distinguishing the two minerals.