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Material World
Mineral · Ag2S

Acanthite

Silver sulfide — the principal silver ore, and the mineral behind the silver rushes that built cities.

Ore

Acanthite is silver sulfide and the most important ore of silver. It is soft, very heavy, and *sectile* — it can be cut with a knife like lead rather than shattering, which is an unusual property and a reliable test.

The mineral carries a naming subtlety worth stating. Above about 175 °C silver sulfide is cubic and is called argentite; below that it is monoclinic acanthite. Argentite crystals therefore do not survive: what look like silver sulfide cubes are acanthite that has inverted while keeping the older shape. Specimens labelled argentite in older collections are acanthite.

Economic significance

Most silver today is a by-product of lead, zinc and copper mining rather than the object of it, but where silver is mined for itself acanthite is what is mined. The great silver districts — Potosí, Zacatecas, the Comstock — were worked for this mineral and the ones that weather from it.

The consequences of that silver reached well beyond mining: the flow of American silver into global trade from the sixteenth century onwards is one of the clearest cases of a mineral reshaping economies far from where it was dug.

Medium confidence Weak evidence

How we know: checked recently · only one source, so there is nothing to cross-check it against · stated directly by the source.

How this connects

Where a connection has been confirmed by an outside reference, that reference is named beside it.

is an ore of

  • Silver — element · the principal ore where silver is mined for its own sake rather than as a by-product Wikidata

is an alternative to

  • Galena — mineral · as a source of silver, and the two are not comparable in volume. Most silver is a by-product of lead mining and comes from galena that happens to carry it; acanthite is what is mined where silver is the object rather than the bonus

is a component of

  • Epithermal vein — deposit type · the silver sulfide, deposited where the fluid boiled — which is why epithermal silver ore stops so abruptly with depth

contains

Sources

  • Material World
    Our own writing
  • Wikidata
    Wikimedia Foundation · Creative Commons CC0 1.0 Universal (public domain dedication)
  • Crystallography Open Database
    COD Advisory Board / Vilnius University · CC0 — contributors place data in the public domain

Questions this page answers

Where it comes from, and what it becomes

Follow Acanthite back to what it starts as, and forward into what it becomes. Each step is a documented one — a real route material takes, not a chain of inference.

Downstream — what it becomes

  • Acanthite → is an ore of (the principal ore where silver is mined for its own sake rather than as a by-product) → Silver → is a component of (a few per cent in the lead-free alloys, which measurably raised world silver demand when the transition happened) → Solder → is used in (every joint on it, and tin-silver-copper since RoHS pushed the lead out from 2006) → Printed circuit board → is used in (and it is the change that made electronics manufacturable: assembly stopped being a wiring job and became a printing one) → Electronics manufacture → is associated with (and the supply chain it produced is the deepest and most concentrated in the world economy) → The semiconductor era complete chain
  • Acanthite → is a component of (the silver sulfide, deposited where the fluid boiled — which is why epithermal silver ore stops so abruptly with depth) → Epithermal vein
  • Acanthite → is an ore of (the principal ore where silver is mined for its own sake rather than as a by-product) → Silver → is used as (in ethylene oxide production) → Catalysis
  • Acanthite → is an ore of (the principal ore where silver is mined for its own sake rather than as a by-product) → Silver → is used as (as the paste forming the contact grid on a silicon cell) → Photovoltaics
  • Acanthite → is an ore of (the principal ore where silver is mined for its own sake rather than as a by-product) → Silver → is a component of (the main component of the dental powder, and what makes the set filling strong) → Amalgam
  • Acanthite → is an ore of (the principal ore where silver is mined for its own sake rather than as a by-product) → Silver → is a component of (the balance, which pales the colour and hardens the metal) → Electrum

These are the most distinct paths onward. Acanthite ends up in others besides.