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Material World
Mineral · Sb2S3

Stibnite

Antimony sulfide, in soft steel-grey blades — the ore of antimony, and the kohl of the ancient world.

Ore Pigment

Stibnite forms long steel-grey blades with a bright metallic lustre, soft enough to mark paper and easily bent. It is the only significant ore of antimony, and antimony's principal modern use is as a flame retardant, generally working alongside a brominated compound.

It is also one of the oldest cosmetics. Ground stibnite is kohl, used around the eyes across the ancient Mediterranean and Near East, and the practice is documented well enough that the mineral's chemical symbol — Sb, from *stibium* — is a fossil of it.

How to identify it

Bladed or acicular crystals, lead-grey, metallic and very soft at hardness 2 — softer than a fingernail will suggest for something that looks so metallic. It melts in a candle flame, which is an old and unusually decisive field test.

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

  • Antimony — element · essentially the only ore of antimony Wikidata

is an input to

  • Roasting — process · roasted to the oxide before reduction

is commonly confused with

  • Bismuthinite — mineral · both soft, bladed and lead-grey; bismuthinite is markedly denser

is a component of

  • Epithermal vein — deposit type · with arsenic below the mercury and above the precious metals, in the same zoned column

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 Stibnite 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

  • Stibnite → is an input to (roasted to the oxide before reduction) → Roasting → produces (as the oxide, which is then reduced — roasting is the step that makes zinc sulfide smeltable) → Zinc → is an input to (the addition that makes brass; it boils below copper's melting point, which is the difficulty) → Alloying and melting → produces (zinc dissolved into molten copper, under conditions that stop the zinc boiling off) → Brass → is used as (in air rather than seawater — brass dezincifies in chloride) → Corrosion protection
  • Stibnite → is an ore of (essentially the only ore of antimony) → Antimony → is a component of (the principal hardener in modern pewter) → Pewter → is used as (the reason it existed: cast cheaply on a domestic hearth, cleanable, and recastable when it dented — the tableware of ordinary European households for five centuries) → Tableware and vessels
  • Stibnite → is a component of (with arsenic below the mercury and above the precious metals, in the same zoned column) → Epithermal vein
  • Stibnite → is an ore of (essentially the only ore of antimony) → Antimony → is used as (hardens lead, and expands on freezing to fill a mould completely) → Alloying
  • Stibnite → is an ore of (essentially the only ore of antimony) → Antimony → is used as (antimony's principal use, generally alongside a brominated compound) → Flame retardancy
  • Stibnite → is an input to (roasted to the oxide before reduction) → Roasting → produces (as the oxide, which is then reduced — roasting is the step that makes zinc sulfide smeltable) → Zinc → is a source for (recovered almost entirely from zinc refining, so indium supply is set by zinc demand) → Indium → is used as (as the transparent electrode in displays) → Lighting

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