Neha Patil (Editor)

Holmquistite

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Category
  
Inosilicate

Dana classification
  
66.1.2.9

Strunz classification
  
9.DD.05

Crystal system
  
Orthorhombic

Holmquistite

Formula (repeating unit)
  
☐{Li2}{Mg3Al2}(Si8O22)(OH)2

Crystal class
  
Dipyramidal (mmm) H-M Symbol: (2/m 2/m 2/m)

Holmquistite is a lithium magnesium aluminium inosilicate mineral with chemical formula: Li2(Mg,Fe2+)3Al2Si8O22(OH)2. It crystallizes in the orthorhombic crystal system as prismatic crystals up to 10 cm (3.9 in) or as massive aggregates. It has a Mohs hardness of 5-6 and a specific gravity of 2.95 to 3.13.

Color could vary from black, dark violet to light sky blue.

It occurs as metasomatic replacements on the margins of lithium rich pegmatites.

It was first described in 1913 from an occurrence in Utö, near Stockholm, Sweden. It was named for the Swedish petrologist Per Johan Holmquist (1866–1946).

References

Holmquistite Wikipedia