Scheelite
Calcium tungstate — a tungsten ore that fluoresces a startling blue-white, which is how it was prospected before instruments.
Scheelite is a calcium tungstate and one of the two minerals the world's tungsten comes from. It is unusually heavy for something that is not obviously metallic — nearly six times the density of water — and that heft is the first clue in the hand.
The second is fluorescence. Under short-wave ultraviolet light scheelite glows an intense blue-white, brightly enough that prospectors worked deposits at night with a lamp. Few minerals give so unambiguous a field test, and fewer still one that can be applied to a whole hillside at once.
Uses
Tungsten's value is its melting point, the highest of any metal, and its hardness as a carbide. Scheelite is processed to tungsten trioxide and onward to the metal or to tungsten carbide, which is the cutting edge on most machine tooling.
The element is also on most critical-materials lists, because production is concentrated and no substitute matches carbide for hardness at the price.
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
- Tungsten — element · one of the two commercial tungsten ores Wikidata
is an input to
- Smelting — process · after conversion to the oxide
- Froth flotation — process · with a fatty acid collector rather than a xanthate, calcium minerals needing a different chemistry from sulfides
is a component of
- Skarn — rock · the tungsten mineral, and the reason skarn is the dominant source of that metal worldwide
Sources
- Material WorldOur own writing
- Wikimedia Foundation · Creative Commons CC0 1.0 Universal (public domain dedication)
- COD Advisory Board / Vilnius University · CC0 — contributors place data in the public domain