64 pages, full colour.

Chywoon Quarry, which works the Carnmenellis Granite, is located between Falmouth and Helston in southwest Cornwall. It has produced some of the finest specimens of pegmatite minerals known from the British Isles. The quarry is a locally owned operation, which was opened in the nineteenth century to produce dressed stone. It was subsequently abandoned, but reopened in the 1960s for aggregate. Between 1995 and 2000 a series of pegmatite pockets lined with large crystals of K-feldspar and quartz, and containing other minerals including albite, muscovite, fluorapatite and fluorite were encountered. A number of large and fine specimens of blue, green and purple prismatic fluorapatite with crystals up to 20 mm long and dark purple cubo-octahedral fluorite of a comparable size were produced from three large cavities. A few hand specimens of bertrandite and calcite were also found. Late stage lower temperature minerals present in the pegmatite cavities include the zeolites stilbite and laumontite as well as torbernite and autunite which are likely to have formed by supergene oxidation. This is one of the most mineralogically remarkable pegmatite discoveries ever made in Cornwall.
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Kainosite-(Y) occurs as a rare late-stage primary mineral at Corrantee and Whitesmith mines, and at the Strontian Barite Mine, north of the village of Strontian, Highland Region, Scotland. It is a minor component of the late-stage primary assemblage and is associated with the zeolite group minerals brewsterite and harmotome and the strontium rare earth carbonate ancylite-(Ce). Kainosite-(Y) occurs as yellow, white to colourless radiating aggregates of acicular, prismatic or platy crystals, which do not usually exceed 1 mm in length. The Strontian localities together with a discovery from the Cuillin Granite on the Isle of Skye are the first records of kainosite-(Y) in the British Isles

Left: A single euhedral pink bipyramid of ancylite-(Ce), 0.8 mm across from Whitesmith Mine with radiating spherulitic aggregates of lath-like kainosite-(Y) 0.3 mm across on brown crusts of chamosite. Centre: White to yellow balls of kainosite-(Y) to 0.5 mm on brown chamosite crusts which are poorly attached to scalenohedral calcite from Whitesmith Mine. Right: White sprays of kainosite-(Y) to 0.1 mm overgrowing scalenohedral calcite crystals which are capped and overgrown by later generation tabular crystal, from the Strontian Barite Mine. Photos: Julie Ballard

Arsenogoyazite occurs as opaque white pseudo-cubic crystals in cavities in quartz veinstone collected from the dumps at Wheal Cock, St Just, Cornwall. The crystals show complex chemical substitutions. They are fluoride, sulphate and phosphate-rich and contain significant calcium and barium. This is the first report of arsenogoyazite in the British Isles.

The rare lead chromate-vanadate mineral cassedanneite has been identified as minute yellow to orange-yellow rhombs on specimens collected from the dumps surrounding Lady Anne Hopetoun Shaft at Leadhills, South Lanarkshire, Scotland. It occurs rarely in oxidised cellular quartz matrix with mottramite. This is the first record of the mineral in the British Isles and the third supergene chromate to be reported from the Leadhills-Wanlockhead mining district.

New Cliffe Hill Quarry near Stanton under Bardon in Leicestershire was opened in the mid-1980s to work an altered diorite rock of late Precambrian age for aggregate. In the early 1990s, a mineralised structure containing a large quantity of copper and cuprite was exposed at the unconformity between the overlying Triassic sediments and the Precambrian basement. Cavities in the copper-cuprite matrix and in fractures in the surrounding rock contained a remarkable suite of copper-bearing supergene minerals including azurite, brochantite, chalcophyllite, connellite, cuprite, libethenite, malachite, spangolite, strashimirite, torbernite, vésigniéite, volborthite and zálesíite. Small amounts of the lead-bearing species cerussite, pyromorphite, mottramite and vanadinite were also identified. In 2002, a new basic copper chloride mineral, bobkingite, named for Dr Robert J. King, a mineralogist with an extensive publication record on the English Midlands, was described from the quarry.

The main copper assemblage found at New Cliffe Hill Quarry comprises major amounts of cuprite, copper and malachite. Other minerals are uncommon but include trace amounts of silver, tenorite, the copper sulphides chalcocite/djurleite, yarrowite and the rare copper-arsenic species algodonite and domeykite. Analyses of domeykite (Cu2.99As) show it to be close to its stoichiometric formula Cu3As but algodonite has a range of compositions from Cu5.39As to Cu6.07As. This paper presents the first analyses of algodonite in Britain that are close to its stoichiometric formula. A minor sulphide assemblage from New Cliffe Hill Quarry carries chalcopyrite, bornite, ‘chalcocite’, spionkopite, yarrowite and covelline and in many respects has a similar petrography to the sulphide assemblage seen at Judkins Quarry where bornite (and its alteration product ‘idaite’), chalcopyrite, minor tetrahedrite, trace amounts of possible cobaltite and blue copper sulphides including geerite, djurleite, digenite, spionkopite and yarrowite occur. An origin for the copper from Permo-Triassic red beds rather than spatially associated Precambrian igneous rocks is favoured.