Judging quality
Sectile — it can be cut with a knife like lead — and extremely heavy. Crystals are dull black with occasional bright metallic faces.
Sulfide
Acanthite
Silver sulfide, the principal ore of silver, in sooty black crystals with a metallic sheen. Mexican specimens often intergrow with native silver wires.
Care
Soft and easily marred. Handle by matrix, keep dust-free, store dry.
History & lore
Guanajuato and Zacatecas silver reshaped the global economy from the 1540s onward, and their ores were largely acanthite.
Cultural history, recorded as tradition rather than as medical or scientific claim.
Common questions about Acanthite
- What is Acanthite?
- Silver sulfide, the principal ore of silver, in sooty black crystals with a metallic sheen. Mexican specimens often intergrow with native silver wires.
- How hard is Acanthite and what is it made of?
- Acanthite is a Sulfide-family mineral with the composition Ag2S. It crystallizes in the monoclinic system and rates 2-2.5 on the Mohs hardness scale. It occurs in black, lead grey.
- Where does Acanthite come from?
- Notable localities for Acanthite include Guanajuato, Mexico, Freiberg, Germany, Nevada, USA, Morocco.
- How do you tell good Acanthite from filler?
- Sectile — it can be cut with a knife like lead — and extremely heavy. Crystals are dull black with occasional bright metallic faces.
- How do you care for Acanthite?
- Soft and easily marred. Handle by matrix, keep dust-free, store dry.
See it in person
Photographs only go so far
Both rooms are open six days a week, and there is always someone happy to pull pieces out of the case so you can compare them under the light.