Gilalite

Gilalite

Blue Gilalite cystals
General
Category Silicate mineral
Formula
(repeating unit)		 Cu5Si6O17·7(H2O)
Strunz classification 09.HE.05
Crystal symmetry monoclinic
Unit cell a= 13.38 Å b= 19.16 Å c= 9.026 Å; β ≈ 90°; Z = 4
Identification
Formula mass 884.3g/mol
Color Blue green, green
Crystal habit Raidiating fibrous in spherules
Crystal system Monoclinic
Tenacity Waxy or gummy
Mohs scale hardness 2
Luster Nonmetallic
Streak Light green
Diaphaneity Translucent
Specific gravity 2.72
Optical properties Biaxial (-)
Refractive index nα= 1.560 nβ=1.635 nΎ= 1.635
Birefringence δ = 0.075
References [1][2][3]

Gilalite is a copper silicate mineral with chemical composition of Cu5Si6O17·7(H2O).[3]

It occurs as a retrograde metamorphic phase in a calc-silicate and sulfde skarn deposit. It occurs as fracture fillings and incrustations associated with diopside crystals.[2] It is commonly found in the form of spherules of radial fibers.

Gilalite inclusions within a quartz crystal from Juazeiro do Norte, Ceara State, Brazil (size: 7.1 x 4.7 x 2.7 cm)

It was first described for an occurrence in the Christmas porphyry copper mine in Gila County, Arizona in 1980 along with the mineral apachite.[4] It derives its name from this locality. It has also been reported from the Goodsprings District, Clark County, Nevada; Juazeiro do Norte, Ceara State, Brazil and a slag area in Lavrion District, Attica, Greece.[3]

References

  1. ↑ gilalite - Wolfram Alpha
  2. 1 2 Handbook of Mineralogy
  3. 1 2 3 Gilalite: Gilalite mineral information, Mindat.org
  4. ↑ F.P. Cesbron and S.A. Williams; March 1980;"Apachite and gilalite, two new copper silicates from Christmas, Arizona" Mineralogical Magazine, Vol. 43, pp. 639-41


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