Supergene Cu, Pb, Zn and Ag Minerals from Force Crag Mine, Coledale, Cumbria

David I. Green
David McCallum
Mike Wood

A suite of supergene minerals from a small oxidised area of the galena-sphalerite-barite orebody at Force Crag Mine is described. Species present include pyromorphite, cerussite, silver, acanthite and a number of rare Cu, Pb, and Zn sulphates.

Brown pyromorphite crystals to 10 mm on a brecciated wallrock fragment.

MINERAL NOTES

Stilpnomelane from Penberthy Croft mine a second Cornish occurrence
John Betterton

Schulenbergite from Nentsberry Haggs Mine, Cumbria
Norman Thompson

Wulfenite from Wheal Ludcott, Cornwall
David Green - Mike Merry

Chenite from Esgait Hir Mine, Talybont, Dyfed
Steve Rust

Rutile from Wheal Remfrey China Clay Pit, Indian Queens, St. Enoder, Cornwall
Christine M. Hacker

Symplesite from Sandbeds Gill Mine, Cumbria
Norman Thompson

The Mineral Collection of the Royal Institute of Cornwall

Roger D. Penhallurick

The Royal Cornwall Museum houses perhaps the finest regional mineral collection in the British Isles.

It includes the world famous Philip Rashleigh collection, which contains many exceptional Cornish mineral specimens, as well as minerals from classic localities elsewhere in Britain and abroad.

Azurite (41 mm across) on quartz. This specimen is figured in Sowerby (1804, table XCIV). The accompanying description reads:

"The present specimen is a very rare and curious modification of carbonate of copper. At present I only know of two specimens; one belonging to P. Rashleigh, Esq., and the other in the possession of Mr. R. Phillips.

The upper figure which belongs to the former gentleman is, as he observes, remarkable for being on the broken end of a large milky rock crystal ..."

The Mineralogy of Ystrad Einion Mine, Dyfed, Wales

John S. Mason
Steve A. Rust

Ystrad Einion mine is a small working situated near Machynlleth, in the Central Wales Orefield.

Several distinct phases of primary mineralisation can be distinguished. Supergene oxidation has given rise to a suite of copper, lead, zinc and iron secondary minerals. Most of these appear to have formed by post-mining oxidation processes. The post-mining mineral suite includes the rare minerals schulenbergite and ktenasite, and the first Welsh occurrence of beudantite.

Serpierite rosettes to 5 mm, collected underground at Ystrad Einion mine. Steve Rust collection.

BOOK REVIEWS

Agate Microstructure and Possible Origin
by Trevor Moxon (1996)
David Green

Laurion The Minerals of Ancient Slags
by Piet Gelaude, Piet van Kalmthout and Christian Rewitzer (1996)
Trevor Wolloxall

Minerals of South Africa
by Bruce Cairncross and Roger Dixon (1995)
David Green