Corsi Collection of Decorative Stones

view of stone 796

Corsi 796, approx. 145 x 73 x 40 mm, © Oxford University Museum of Natural History

OUMNH Number: 796  
Name and quarry location: most probably Lapis Iaracites, porfido verde Egiziano, from Gebel Dokhan, Eastern Desert, Egypt  
Geological description: Andesite-dacite porphyry of white plagioclase phenocrysts in a grey-black groundmass. Very minor epidotisation of the plagioclase.  
Comments: This is most probably the green-black 'porfido verde' from Gebel Dokhan (the ancient Mons Porphyrites) in the Eastern Desert of Egypt. A better example is no. 787. Russia is not noted for its decorative porphyries, and those of Egypt (like nos. 783-788) and Sweden (no.795) are commonly used there. The Russian stone most often known as 'porphyry' is the Shoksha porphyry, actually a quartzite (Bulakh, 2010).  
References: Borghini (1997) 278; Brindley (1887); Bulakh (2010) passim.; Harrell (2010a); Lazzarini (2002c) 233-235; Mielsch (1985) 65, taf.21; Price (2007) 202-203  
Further information:
 


Corsi's classification: Class 15. Porphyry; Species 1; ii. Italian porphyries  
Corsi's text: 196.8 Porfido di Siberia  

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