Tyrrellite

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title: "Tyrrellite" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["copper-minerals", "cobalt-minerals", "nickel-minerals", "selenide-minerals", "thiospinel-group", "cubic-minerals", "minerals-in-space-group-227"] topic_path: "general/copper-minerals" source: "https://en.wikipedia.org/wiki/Tyrrellite" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::data[format=table title="Infobox mineral"]

Field	Value
name	Tyrrellite
category	Selenide mineral
Thiospinel group
(Spinel structural group)
image	Tyrrellite, Chalcomenite, Umangite-652476.jpg
formula
IMAsymbol	Ty
strunz	2.DA.05
system	Isometric
class	Hexoctahedral (mm)
H-M symbol: (4/m 2/m)
symmetry	Fdm
unit cell	a= 10.005 Å; Z = 8
color	light bronze
habit	granular
cleavage	{001} Distinct
fracture	conchoidal
tenacity	brittle
mohs	3.5
luster	metallic
streak	black
gravity	6.6 ± 0.2
diaphaneity	Opaque
references
::

| name = Tyrrellite | category = Selenide mineral Thiospinel group (Spinel structural group) | boxwidth = | image =Tyrrellite, Chalcomenite, Umangite-652476.jpg | caption = | formula = | IMAsymbol = Ty | molweight = | strunz = 2.DA.05 | system = Isometric | class = Hexoctahedral (mm) H-M symbol: (4/m 2/m) | symmetry = Fdm | unit cell = a= 10.005 Å; Z = 8 | color = light bronze | habit = granular | twinning = | cleavage = {001} Distinct | fracture = conchoidal | tenacity = brittle | mohs = 3.5 | luster = metallic | refractive = | opticalprop = | birefringence = | pleochroism = | streak = black | gravity = 6.6 ± 0.2 | density = | melt = | fusibility = | diagnostic = | solubility = | diaphaneity = Opaque | other = | references =

Tyrrellite is a selenide mineral that has a chemical formula of .

Crystallography

Tyrrellite is isometric, meaning that crystallographically, it has three axes of equal length perpendicular to one another. It belongs to the space group, Fd3m. Tyrrellite displays a light bronze color when viewed in plane polarized light. Because tyrrellite is isotropic, the light bronze color will remain constant as the mineral is rotated and viewed from different crystallographic angles. When viewed under cross polarized light, tyrrellite displays total extinction, a characteristic trait of isotropic minerals.

Discovery and occurrence

It was first described in 1953 for an occurrence in the Goldfields District, Saskatchewan, while the second occurrence was reported in Petrovice deposit, Czech Republic. In general, tyrrellite is veined, embayed and replaced by umangite, a primary mineral of deposits in which tyrrellite is found. The relative scarcity and unique occurrences of tyrrellite can give geologists considerable insight into the circumstances under which the parent rock formed.

References

References

1. Warr, L.N.. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine.
2. [http://webmineral.com/data/Tyrrellite.shtml Webmineral data]
3. [http://rruff.geo.arizona.edu/doclib/hom/tyrrellite.pdf Handbook of Mineralogy]
4. [http://www.mindat.org/min-4071.html Mindat.org]
5. Robinson, S.C. and Brooker, E.J. (1952) A cobalt-nickel-copper selenide from the Goldfields District, Saskatchewan. American Mineralogist, 37, 542-544.
6. It has been found in the Goldfields District in northern [[Saskatchewan]], as well as in the Petrovice deposit, [[Czech Republic]]. It is named after the Canadian geologist [[Joseph Burr Tyrrell]]. Joseph Tyrrell was one of the first geologists from the Geological Survey of Canada to do research in the Goldfields District.Harris, D.C. (1970) New Data on Tyrrellite. The Canadian Mineralogist, 10, 731-735.
7. Because tyrrellite is isometric, it is also isotropic. Isotropic minerals are defined as follows: when light passes through an isometric mineral, the light moves in all directions with equal velocity. In contrast, for anisotropic minerals, the velocity of light passing through the mineral varies with crystallographic direction.Klein, C., Dutrow, B. (2007) The 23rd edition of the Manual of Mineral Science. John Wiley Publishers, p. 290

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