Alum-(K)

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Alum-(K)
Specific gravity
1.757
Optical propertiesIsotropic
Refractive indexn=1.453
SolubilityWater soluble
References[2][3][4]

Alum-(K) is a hydrous potassium aluminium sulfate mineral with formula KAl(SO4)2·12(H2O). It is the mineral form of potassium alum and is referred to as potassium alum in older sources. It is a member of the alum group.[2]

It occurs as colorless to white, soft isometric crystals and efflorescence coatings.[3] Rare crystals are octahedral in form if occurring as precipitates from neutral water solution, but cubic in form if the solution is alkaline.[2]

It occurs as a precipitate around volcanic

native sulfur.[3]

Occurrences include Mount Vesuvius, Italy and Alum Cave, Sevier County, Tennessee.[3][4]

References

  1. S2CID 235729616
    .
  2. ^ a b c Alum-(K) on Mindat
  3. ^ a b c d Potassium alum on Handbook of Mineralogy
  4. ^ a b Alum-(K) data on Webmineral


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