Reidite

Reidite
General
Category Zircon group
Formula
(repeating unit)		 ZrSiO4
Strunz classification 9.AD.45
Crystal system Tetragonal
Crystal class Dipyramidal (4/m)
H-M symbol: (4/m)
Space group I41/a
Unit cell a = 4.738, c = 10.506 [Å], Z = 4
Identification
Formula mass 183.31 g/mol
Color Colorless to white
Crystal habit

Epitaxial - crystallographic alignment with a precursor mineral,

occurs as inclusions in other minerals.
Cleavage None
Fracture Irregular/uneven
Tenacity Brittle
Mohs scale hardness 7.5
Luster Adamantine
Streak White
Diaphaneity Translucent
Specific gravity 5.16
Optical properties Uniaxial (+)
Refractive index nω=1.64, nε=1.655
Birefringence 0.0150
Pleochroism None
References [1][2]

Reidite is a rare mineral that has been found only in four crater impacts: the Chesapeake Bay Crater in Virginia, Ries Crater in Germany, Xiuyan Crater in China, and Rock Elm Crater in Wisconsin in the United States.[3]

In 2015 an occurrence of reidite was reported from the Precambrian Stac Fada Member structure in North West Scotland, confirming its impact origin.[4]

Name origin

Reidite is named after the scientist who first created the high pressure phase in the laboratory in 1969, Alan F. Reid.

Formation

Zircon morphs into reidite when shock waves from meteorite impacts hike up pressures and temperatures to extreme levels, equal to those deep inside the Earth where diamonds form. The pressure makes minerals tightly repack their molecules into denser crystal structures. Reidite has the same composition as regular zircon but is about 10 percent denser.[3]
Relationship of Reidite to Other Specimen
9.AD.25 Uvarovite Ca3Cr2(SiO4)3
9.AD.25 Wadalite (Ca,Mg)6(Al,Fe3+)4((Si,Al)O4)3O4Cl3
9.AD.25 Holtstamite Ca3(Al,Mn3+)2(SiO4)2(OH)4
9.AD.25 Kerimasite Ca3Zr2(SiO4)(Fe3+O4)2
9.AD.25 Toturite Ca3Sn2(SiO4)(Fe3+O4)2
9.AD.25 Momoiite (Mn2+,Ca)3V23+(SiO4)3
9.AD.25 Eltyubyuite Ca12Fe103+Si4O32Cl6
9.AD.25 Hutcheonite Ca3Ti2(SiAl2)O12
9.AD.30 Coffinite (U4+,Th)(SiO4)1-x(OH)4x
9.AD.30 Hafnon HfSiO4
9.AD.30 Thorite (Th,U)SiO4
9.AD.30 Zircon ZrSiO4
9.AD.30 Stetindite Ce4+SiO4
9.AD.35 Huttonite ThSiO4
9.AD.35 Tombarthite-(Y) Y4(Si,H4)4O12−x(OH)4+2x
9.AD.40 Eulytine Bi4(SiO4)3

See also

References

  1. ↑ "Reidite". mindat.org. Hudson Institute of Mineralogy. Retrieved 18 March 2015.
  2. ↑ "Reidite Mineral Data". Webmineral.com. Retrieved 18 March 2015.
  3. 1 2 Oskin, Becky. "Rare Mineral Discovered in Ancient Meteorite Impact Crater". Livescience.com. Livescience. Retrieved 24 March 2015.
  4. ↑ Reddy, S. M., et al. "Precambrian reidite discovered in shocked zircon from the Stac Fada impactite, Scotland." Geology (2015): G37066-1.
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