Corsi Collection of Decorative Stones

view of stone 664

Corsi 664, approx. 145 x 73 x 40 mm, © Oxford University Museum of Natural History

OUMNH Number: 664  
Name and quarry location: Pietra dell'Etna, from Mt. Etna, Catania, Sicily, Italy  
Geological description: Altered (?phonolitic) tephrite. A porphyritic rock with prominent euhedral megacrysts of black pyroxene, and with an altered euhedral pale mineral forming less obvious phenocrysts. The groundmass is very fine-grained, fawn-coloured, and of indeterminate mineralogy. This sample has some similarities with no. 665 but is lighter in colour, possibly because of alteration.  
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Corsi's classification: Class 8. Volcanic stones; ii. Stones from Etna  
Corsi's text: 157.20 Pietra dell'Etna  

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