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Mineral · SnO2

Cassiterite

Tin dioxide, and effectively the only tin ore of economic importance.

Ore

Cassiterite is unusual among ore minerals in having almost no competition: virtually all tin ever produced has come from it. It is also unusually dense for a non-metallic-looking mineral, at around seven times the density of water, which is what made it recoverable by the simplest possible method.

Extraction

Cassiterite's density and its resistance to weathering mean it survives erosion and concentrates in stream gravels. That made it recoverable by panning and sluicing — no chemistry, no furnace, just water and a sense of what settles first. This is why tin was available to Bronze Age societies at all: it required no technology they did not have.

How to identify it

Cassiterite is unusually heavy for a non-metallic-looking mineral — a density near seven puts it well above almost anything it is found with, which is precisely why panning and gravity separation recover it so effectively.

It is hard enough to scratch glass easily, and shows an adamantine to greasy lustre on fresh fracture. Colour ranges from near-black through red-brown to, rarely, near-colourless, but the streak is always pale — white to brownish — which separates it at once from the dark heavy oxides it resembles.

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.

contains

  • Tin — element Wikidata
  • Oxygen — element Wikidata

is an ore of

  • Tin — element · the only tin ore of economic importance Wikidata

is an input to

  • Smelting — process · reduced with carbon to metallic tin

is found at

is used as

  • Alloying — application · the ore from which tin reaches bronze and solder

is a component of

  • Greisen — rock · the tin oxide, dropped out of the vapour as it cooled — the ore the rock is mined for

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 Cassiterite 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

  • Cassiterite → is an ore of (the only tin ore of economic importance) → Tin → is an input to (the addition that hardens copper into bronze) → Alloying and melting → produces (tin into copper — the first alloy anybody made deliberately) → Bronze → is used to make (cast in a two-piece mould with a core, which is what bronze does better than the copper it replaced) → Bronze socketed axe → is associated with → Bronze Age complete chain
  • Cassiterite → is an input to (reduced with carbon to metallic tin) → Smelting → produces (as blister copper, refined electrolytically afterwards) → Copper → is a component of → Bronze → is used to make (cast in a two-piece mould with a core, which is what bronze does better than the copper it replaced) → Bronze socketed axe → is associated with → Bronze Age complete chain
  • Cassiterite → is used as (the ore from which tin reaches bronze and solder) → Alloying
  • Cassiterite → is a component of (the tin oxide, dropped out of the vapour as it cooled — the ore the rock is mined for) → Greisen
  • Cassiterite → is an ore of (the only tin ore of economic importance) → Tin → is a component of (the component that hardens the copper and lowers its melting point) → Bronze → is used to make (cast in a two-piece mould with a core, which is what bronze does better than the copper it replaced) → Bronze socketed axe → is associated with → Bronze Age complete chain
  • Cassiterite → is an ore of (the only tin ore of economic importance) → Tin → is used as (the addition that turns copper into bronze) → Alloying

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