Mineral Information and Data:

ZrSiO4 [CNMNC approved formula]

Named from the Arabic (and, in turn, from the Persian "azargun") "zar", gold, plus "gun", colored, referring to one of the many colors that the mineral may display.

IMA status : Valid species (Pre-IMA Ancient) Grandfathered
(8th edition) :  
  (51) Nesosilicate Insular SiO4 Groups Only
  (51.05) with cations in >[6] coordination
  (51.05.02) Zircon group
(10th edition) :
  (09) Silicates
  (09.A) Nesosilicates (Isolated tetrahedron) structures
  (09.AD) Nesosilicates without additional anions; cations in [6] and/or greater coordination
Crystal system: Tetragonal System
Point group (H-M): 4/mmm (or 4/m 2/m 2/m) — ditetragonal-dipyramidal
Unit cell: a = 6.604 Ǻ, c = 5.979 Ǻ
Crystal Habit: Crystals short to long prismatic, or dipyramidal; sheaf-like or radial-fibrous aggregates; irregular grains
Twinning: On {101}, geniculate; also on {011}
Color: Colorless, brown, green, gray, yellow, red
Diaphaneity: Transparent to opaque if metamict
Luster: Vitreous to adamantine
Hardness (Mohs): 7.5
Measured Density: 4.6 to 4.7 g/cm3
Cleavage: 2; {110} imperfect, {111} poor
Tenacity: Brittle
Fracture: Conchoidal
Streak: White
Polymorphism and Series: Diamorphous with Reidite.
Geologic Setting: An accessory mineral in igneous and metamorphic rocks, with crystals reaching large size in mafic pegmatites and carbonatites; in sedimentary rocks and alluvial heavy-mineral sands
Mineral Association: Feldspars, amphiboles, mica, quartz
Ore deposits: Primary ore mineral of hafnium.
Luminescent Properties: Thermoluminescent, cathodoluminescent, may fluoresce under UV.
Other Properties: Radioactive. Gemstone Readily Available.
Comments: Radioactive when metamict;


Origin: Tvededalen, Langesundfjord, Norway
Picture height: 5 mm
Sample owner: Mr. and Mrs. Stemvers-van Bemmel
Photo: Pieter Stemvers, Leusden, Netherlands


Origin: Kipawa Rare Earth Complex, Temiscamingue Co., Quebec, Canada
Sample size: 5 x 4.5 x 2 cm
Photo: Tom Loomis


(zoom-in of above)


Micro brown crystals to about 0.5 mm in orthoclase matrix
Origin: Crestmore quarry, Riverside Co., California, United States
Sample size: 8 x 4 x 4 cm
Photo: Tom Loomis


(zoom-in of above)