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Material World
Mineral · Cu3(CO3)2(OH)2

Azurite

The blue copper carbonate that slowly becomes the green one — which is why so many old skies have turned to foliage.

Pigment Ore

Azurite forms in the same weathered copper deposits as malachite and is the deeper blue of the two. The pair are almost always found together, and the reason is that azurite is the less stable: given time and moisture it converts to malachite, keeping the crystal shape and changing the colour entirely.

That conversion is visible in art. Azurite was the everyday blue of medieval and Renaissance painting — ultramarine being ruinously expensive — and a good deal of it has since turned green on the panel, which is why skies and robes in some old paintings are not the colour they were made.

How to identify it

Deep azure blue, with a light blue streak and a vitreous lustre, and it effervesces in dilute acid. It is soft, around 3.5 to 4, and commonly intergrown with green malachite — often as a blue core within green.

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

  • Copper — element · a minor secondary ore, almost always worked alongside malachite Wikidata

is an alternative to

  • Chalcopyrite — mineral · the same substitution as malachite and for the same reason — an oxidised copper carbonate leached rather than smelted, from the weathered cap of a sulfide deposit
  • Malachite — mineral · the two oxidised copper carbonates, mined together and treated identically. Azurite is the less stable of the pair and slowly alters to malachite, which is why green outcrops are commoner than blue ones

is a component of

  • Oxidised zone — deposit type · the blue one, less stable than malachite and slowly altering to it, which is why green outcrops outnumber blue

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 Azurite 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

  • Azurite → is an ore of (a minor secondary ore, almost always worked alongside malachite) → 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
  • Azurite → is a component of (the blue one, less stable than malachite and slowly altering to it, which is why green outcrops outnumber blue) → Oxidised zone
  • Azurite → is an ore of (a minor secondary ore, almost always worked alongside malachite) → Copper → is a source for (much of world supply arrives as a by-product of copper mining rather than from cobalt-first operations) → Cobalt → is a component of (the balance, and both the reason it works hot and the reason it is expensive) → Samarium–cobalt magnet → is used as (weaker and untroubled by heat, which keeps it where temperature rather than strength is the constraint) → Permanent magnets
  • Azurite → is an ore of (a minor secondary ore, almost always worked alongside malachite) → Copper → is used as → Electrical conduction
  • Azurite → is an ore of (a minor secondary ore, almost always worked alongside malachite) → Copper → is used as (the base metal of both bronze and brass) → Alloying
  • Azurite → is an ore of (a minor secondary ore, almost always worked alongside malachite) → Copper → is a component of → Bronze → is associated with (the alloy the period is named for) → Bronze Age complete chain

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