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Fluorite, United Kingdom

Posted by Jesse Fisher  
avatar Re: Fluorite, United Kingdom
March 23, 2009 01:07PM
Ralph, I have uploaded something more than 20 images of English fluorite that may help you in your task of trying to find suitable photos. I have a couple of more good ones to up load, but the locality is somewhat up in the air. I took pictures of them in 1975 in the British Museum and the label said Beeralston, Dveon, England, but I can't fine any such locality even close to that on mindat. Can you shed some light on this?

Rock Currier
Crystals not pistols.
avatar Re: Fluorite, United Kingdom
March 23, 2009 02:48PM
    
As last summer, I will be there in June and August.
avatar Re: Fluorite, United Kingdom
March 23, 2009 03:36PM
    
Damn, can't be true. I'm in a Moliere play the whole months of June, August and first half of September (earning this years living....) only July is free.
avatar Re: Fluorite, United Kingdom
March 23, 2009 07:43PM
    
Rock,

It is spelled "Bere Alston" and is a mining area near Tavistock, Devon. Ian Jones is quite familiar with the fluorite from the area.

Harjo,

I'll be in Weardale until July 3, if that helps any. Be fore warned, however, as Frank De Wit is threatening to come for a visit around that time.

Cheers,
Jesse
avatar Re: Fluorite, United Kingdom
March 24, 2009 12:50AM
    
Rock,
Thanks for uploading the photos of English fluorites. As is typical with specimens in older collections the location information on most is only general, and sometimes wrong. For those that I can identify from the photo, I would suggest the following:

220372, 220375, 220382, and 220386 are all likely from the Boltsburn Mine, Rookhope, Co. Durham.
220384 is from the St. Peter's Mine, Spartya Lea, East Allendale, Northumberland.

Jesse
avatar Re: Fluorite, United Kingdom
March 24, 2009 01:23AM
Jessy, I have changed the localities on those whose localities you recognized and added two more images of specimens from Bere Alston.

Rock Currier
Crystals not pistols.
avatar Re: Fluorite, United Kingdom
March 25, 2009 04:42PM
    
probably the mines in devon and cornwall listed below ought to be included

South west England

Whilst the Pennine’s mines undoubtedly produced the lion’s share of quality British fluorite, the south-west has an equally striking combination of colors and crystal habits and deserves more recognition. Many of the south-west’s finest specimens were recovered in the early 1800s when the area’s copper, tin and lead mining flourished

Devon

Bere Alston

First worked in the 13th century, the small silver-lead mining area of Bere Alston in south Devon was one of the south-west’s chief fluorspar producers. Fine specimens were recovered in the early 1800s.

From unspecified mines here are incomplete cubes to 10cm on edge; pale yellow, speckled with 1cm galena crystals and sea-green, part coated with stubby quartz crystals. Pale blue color-zoned 3cm cubes occur on quartz, also groups of rounded pale green frosted crystals to 1.5cm and polysynthetic octahedral crystals to 2.5cm. Intergrown, colorless 2.5cm fluorite cubes with feint purple zoning with 1.5cm chalcopyrite crystals and intergrown yellow crystals with white edges, typically 1.5cm, were also found.

Lockeridge mine produced intergrown yellow crystals to 5cm with dolomite, smaller colorless crystals and sharp 1.5cm cubes replaced by chalcedony. Frosty blue-purple fluorite to 5cm and chalcedony coating intergrown, octahedral fluorite to 2.5cm occurred at East Tamar mine (aka Furzehill mine) together with groups of frosty purple cubes to 1.5 cm with rounded corners; smaller, more modified, crystals form spheroids. At South Tamar mine, opaque grey-purple crystals to 5cm speckled with quartz were found, as were 3.5cm pale yellow crystals. Purple fluorite occurred at Tamar Valley mine (aka Buttspill mine), its small dumps were said to contain 20% fluorite

Menhenniot

Wheal Mary Ann (closed 1875) produced excellent fluorite, some attractively speckled with quartz, galena and pyrite; incomplete cubes have edges to 14 cm! These include colorless with sharp yellow and purple zoning; yellow, with an intense purple edge, on bladed barite; blue-purple; sea-green on quartz, and purple with individual 3.5cm calcite crystals. Intergrown groups of both yellow and purple cubes to 3cm also occurred. Fragments collected from the dumps have yielded cut stones to over 50ct.

Wheal Trealawney (closed 1884) produced fine sulphur-yellow fluorite crystals to 5.5cm and groups of smaller crystals.

Cornwall

Liskeard area

Caradon copper mines (1830s-1880s) produced stepped octahedral blue fluorite partly coated with micro quartz crystals and speckled with purple fluorite and chalcopyrite; also complex groups of rounded pale blue fluorite on quartz. Octahedral blue fluorite to 5.5cm invested with small milky quartz crystals occurred at West Caradon mine, as did light purple fluorite. Yellow fluorite occurred at both West Caradon and South Caradon mines.

Cheezewring quarry produced octahedral purple fluorite to 5.5cm with tiny beudantite crystals, and cubic yellow crystals to 3.5cm with purple zoning.

Holmbush mine produced vivid, electric blue fluorite to 7cm and paler blue fluorite to 12cm.

St Agnes area

Wheal Kine (aka Wh Kind), the type locality for vivianite produced pale green, stepped octahedral fluorite to 3cm, but the area is better known for its lilac to purple tetrahexahedral crystals commonly known as 4-faced cubes; each face having four raised triangular faces. Tetrahexahedral crystals to 2cm, some with greenish centres, occurred in mines of the Polberro group, particularly Trevaunance and Pell mines.

Cambourne/Redruth/St Day mining field

Wheal Gorland, largely closed in the 1860s and the type locality for liroconite, clinoclase, cornwallite and chenevixite, also produced particularly fine fluorite. Pale pink crystals to 5.5cm occurred as did deep blue crystals, some with internal zoning. Pale purple crystals with associated pyrite to 3.5cm were found, also colorless to green stepped 1.5cm crystals, some with chalcopyrite to 2cm and quartz. Many fluorites have diagnostic bevelled, rounded, corroded edges.

Carn Brae mine (closed 1913) produced green, light and dark purple cubes to 5cm, some speckled with 0.5cm chalcopyrite crystals; zoned clear crystals with purple banding and yellow centres; 1cm clear cubes with purple edges and frosted light-blue octahedra, both on red ironstained quartz. Cornwall’s deepest mine, Dolcoath (closed 1913), well known for acicular “sparable” cassiterite, produced colorless fluorite cubes to 4cm on clear elongated quartz crystals. Tincroft mine produced aggregates of colorless to pale purple crystals with greenish cores and purple edges, typically 2cm, some on lenticular, tan-colored siderite with associated chalcopyrite and hematite. East Pool mine (closed 1949) produced stepped light green fluorite with light purple edges and, exceptionally, a large cleaved sea green and yellow crystal with a deep purple core. South Crofty mine later incorporated many of these workings and, prior to closure in 1988, produced fluorite with acicular bismuthenite and hollow siderite epimorphs after fluorite to 3cm. Nearby, Wheal Jane, (closed 1991), the type locality for ludlamite, produced beautiful transparent, stepped green crystals with clear outer zones and purple edges on quartz, and attractive, frosted green crystals, some with purple edges.

West Penwith

St. Ives Consols, best known for world-class chalcocite specimens, produced spectacular sea-green to clear, zoned, cleaved crystals to 22cm with sulphide inclusions around 1812.
avatar Re: Fluorite, United Kingdom
March 25, 2009 07:39PM
Ian, Im sure you are right. Sometimes it seems that the task is to big even to think about. But you know what? I just keep plugging away and after a while the job gets done.

Rock Currier
Crystals not pistols.
avatar Re: Fluorite, United Kingdom
March 27, 2009 12:09PM
    
Some notes on Cornish fluorites:

Camborne/Redruth/St Day:

Wheal Unity: Fluorite was abundant in some parts of the mine. In 2003, when an area the size of a football pitch was cleared for building operations opposite to Wheal Unity gate, several small dumps were cut one of which was composed almost entirely of massive pale green fluorite (rarely with tiny crystals - I had no luck with these, but found a nice clinoclase instead). Decent crystals seem to have been generally scarce.

Wheal Buller: This mine produced yellow, purple and light green crystals, often with slightly rounded edges. Many of the purple crystals have yellow cores. The dumps still produce good specimens (I did collect some in 2007 and 2008).

West Penwith:

Green fluorite was also recovered from Botallack Mine. I don't know much about the quality and whether crystals were found at all (I will ask Dominic Hudson when I see him this summer), but the massive sample I have in my collection (Corpus Christi lode, collected on adit level near Cliff Fields shaft) displays a rather unique "toxic green" colour which I have not seen in fluorites from anywhere else.
avatar Re: Fluorite, United Kingdom
March 27, 2009 01:32PM
    
fluorite is not that uncommon in the southwest, but good specimens are rare.

a number of the clay pits and the the quarries nearby also produce nice fluorite, but i didn't include them as i don't think they rank high enough on the UK scale. I think that probably Wh Buller and Botallack also fall into this category, there is certainly nothing in the BM of note. The Unity/Gorland dumps were covered in massive green fluorite, but I never saw a modern specimen from here that began to compare with old-time pieces unfortunately
Re: Fluorite, United Kingdom
March 27, 2009 02:49PM
Hello Ian,

Thanks for posting the information on Cornish fluorite localities and distinguishing specimen characteristics.

I'm sorting through part of an old Cornish collection that recently came to light in Lostwithiel. Some of the specimens are very good (possibly collected by Talling), but none are labeled. Based on the collection history and many specimens that can be attributed with confidence, the great majority came from the Liskeard District (as defined in Mindat). I'm puzzling over some of the fluorites, however, especially the yellow ones. Do you know of any way to distinguish yellow fluorites from Wheal Mary Ann, Wheal Trelawny, and the Caradon Mines? Do they differ in crystal habit, luster, associations, etc.? The specimen in question has a thin crust of pyrite on the base, as well as patches of micro pyrites on the crystal surfaces. Similar pyrite occurs on a couple of large blue cubic crystals in the collection that most likely came from Mary Ann. One of them is 22 cm across!

Thanks,
Woody Thompson
avatar Re: Fluorite, United Kingdom
March 27, 2009 03:00PM
Woody

Feel free to bring some of the specimens to Rochester and I'll be happy to give my opinions on provenance etc!

Jolyon
Re: Fluorite, United Kingdom
March 27, 2009 03:06PM
Hi Jolyon,

That would be great, thanks. It happens that I'll be exhibiting specimens from the Cornish collection at Rochester, and your locality attributions would be most welcome! It'll also give me a chance to say more about the collection history and some of the related mysteries that we're trying to sort out.

Looking forward to visiting with you and hearing your talk. Alfredo is likewise giving a talk on Mindat, here in Augusta at the Maine Mineral Symposium in May, so we're "spreading the gospel".

Cheers,
Woody Thompson
(Maine Geological Survey)
avatar Re: Fluorite, United Kingdom
March 27, 2009 06:08PM
    
Woody

Yellow with pyrite from trelawney, mary ann and caradon.

not too much to tell them apart really

ian
Attachments:
open | download - trelawney ---- sulphur yellow plus pyrite.jpg (38.6 KB)
open | download - mary ann 1298 yellow & pyrite.jpg (42.7 KB)
open | download - west caradon 1274 yellow.jpg (48.3 KB)
avatar Re: Fluorite, United Kingdom
March 27, 2009 07:16PM
    
some more nice cornish bits

The third attachment is an image of the same specimens in the British Museum that I took a picture of in 1975 and just recently uploaded, but on a black background.
Rock




Edited 1 time(s). Last edit at 03/27/2009 11:03PM by Rock Currier.
Attachments:
open | download - cheesewring 1253 purple oct.jpg (42.6 KB)
open | download - mary ann 1285 clear purple yellow zones.jpg (52.9 KB)
open | download - caradon2.jpg (809.4 KB)
avatar Re: Fluorite, United Kingdom
March 27, 2009 07:23PM
    
three more

these 9 are from my records of things in the BM, ::o will see if i can get decent pictures at some point
Attachments:
open | download - gorland 1200 blue.jpg (52.8 KB)
open | download - gorland 4643 pale pink.jpg (31.4 KB)
open | download - jane.jpg (892.1 KB)
Re: Fluorite, United Kingdom
March 27, 2009 07:26PM
Ian,

Very fine specimens and helpful photos, thanks. I don't have much experience with fluorites from this part of Cornwall, so it's nice to see some examples. I was surprised at the vibrant lemon/sulfur color of the crystals associated with pyrite, and the resemblance between localities. And that last one from Caradon boggles the mind! (:D

Later tonight I'll post a couple of photos of the yellow fluorites with pyrite that I mentioned.
Re: Fluorite, United Kingdom
March 28, 2009 12:04AM
Ian,

Here are top and bottom views of one of the yellow fluorites from the collection that I'm researching. The specimen is 10 x 7 x 7 cm. The color is very pale, and the crystal faces are lightly frosted. Small patches of micro pyrites occur on the crystal surfaces, along with a few tiny weathered galena crystals. The bottom of the specimen is a shallow concave surface lined with botryoidal clusters of micro pyrites.

The presence of galena suggests Wheal Mary Ann or one of the other nearby mines, and not the Caradon area?
Attachments:
open | download - CornishFluorite1A-Top.jpg (122.5 KB)
open | download - CornishFluorite1B-Base.jpg (82.4 KB)
avatar Re: Fluorite, United Kingdom
March 28, 2009 11:06AM
    
hi woody

difficult to say really, but tend to agree that the galena points more towards the menheniot mines rather than the liskeard ones. galena with fluorite is a common association from the former.

three more mary ann rocks to look at. what a place that was!
Attachments:
open | download - mary ann 1845 yellow purple edge barite.jpg (42.6 KB)
open | download - mary ann 1823 purple & calcite.jpg (54.7 KB)
open | download - mary ann 1846 pale sea green.jpg (36 KB)
Re: Fluorite, United Kingdom
March 28, 2009 03:14PM
Nice specimens, Ian! Wheal Mary Ann must have been a real candy box. I've attached photos of other fluorites from the same collection mentioned previously. The first two are top and side views of the large 22 cm blue crystal. It's incomplete on the back, but not damaged, with traces of pyrite in a few places. The blue color is a bit lighter than seen in the photos, and the inside of the crystal is very pale yellow. The unusual size made me think of the Mary Ann blue fluorite cubes to a foot in diameter, which are reportedly in the Natural History Museum. I haven't seen them in person, but they are described on page 86 in F. W. Rudler's 1905 catalog of the Ludlam collection.

The third photo shows sea-green fluorites with stubby quartz xls. The bottom of this specimen has some massive deep blue-green fluorite with a little embedded massive galena. Size of this piece is 14 cm across.

Any thoughts on these? Mary Ann or possibly one of the other mines in the Liskeard district?



Edited 1 time(s). Last edit at 03/28/2009 03:14PM by Woodrow Thompson (2).
Attachments:
open | download - CornishFluorite3A.jpg (114.7 KB)
open | download - CornishFluorite3B.jpg (80.8 KB)
open | download - CornishFluorite4A.jpg (97.9 KB)
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