OUMNH Number: | 540 |
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Name and quarry location: | Fluorite, Blue John, from Derbyshire, England |
Geological description: | Hydrothermal vein deposit of fluorite. The narrow purple-blue colour zone indicates it is the Blue John variety. |
Comments: | This specimen was given to Corsi by the 6th Duke of Devonshire following the Duke's visit to see Corsi's collection in 1824. Blue John, of which nos. 541 and 543 are particularly fine examples, was first discovered at Castleton around 1700, and was mined as an ornamental stone from around 1750 onwards. Fluorite approaching the colour-banding of Blue John has been found in the areas of Crich and Milltown, according to Ford (1993), and so Corsi’s ‘altro dello stesso luogo’ may refer either to Crich (like no. 539) or just to Derbyshire. |
References: | Ford (2000); Price (2007) 266; Webster (1994) 337-341 |
Further information: |
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Corsi's classification: | Class 2. Fluorspars |
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Corsi's text: | 133.3 Altro dello stesso luogo [Spato di Darbyshire] |