Introduction: yarrowite is one of several non-stoichiometric copper sulphide species. By this it is meant that they have compositions which fit in between copper¹⁺ sulphide (chalcocite, Cu₂S), and copper²⁺ sulphide (covelline, CuS). Many of these minerals are recent discoveries as they occur in complex, microscopic intergrowths which have required modern analytical techniques to unravel their detailed mineralogy. The combined techniques of high-resolution ore petrology, X-ray diffraction and electron microprobe analyses are required in order to identify yarrowite and related minerals. Yarrowite occurs, along with the other non-stoichiometric copper sulphides and covelline, in supergene alteration assemblages derived from primary sulphide mineralisation in which copper is an important component. It typically occurs as replacements of the primary minerals, forming rims and veinlets along cleavage-planes and/or grain boundaries

Occurrence in Wales: yarrowite has to date been found at one locality in Central Wales during a high-resolution petrological examination of its ore mineralogy (Ixer, 2003). However, many previously studied assemblages containing 'supergene chalcocite' or covellite-like minerals have only been studied using more basic ore petrology: hence, the current single-locality status of yarrowite in Wales is likely to alter with further examination.

Last saved full search

Alphabetical search:

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

S

T

U

V

W

X

Y

Z