Tarapacaite

Tarapacaite is the mineral form of Potassium chromate; formule K2CrO4. It forms bright yellow crystals and was discovered in 1878 in Tarapaca Province, Chile for which it is named. It is unlikely that this mineral would occur anywhere except in the most arid conditions as it would be easily soluble in water.
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General Information:
 Chemical Formula:
K2CrO4
 Composition:
(Molecular Weight = 194.19 gm)
Potassium 40.27 % K 
Chromium 26.78 % Cr
Oxygen 32.96 % O 
 Empirical Formula:
K2(CrO4)
Physical Properties:
 Cleavage:
[001] Distinct, [010] Distinct
 Color:
yellow or light yellow.
 Density:
2.74
 Diaphaniety:
Transparent
 Luster:
Vitreous (Glassy)
 Streak:
light yellow
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