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200 Mineralogy of Southern India. 



The characters of the rock are as follow. Colour: bluish, 

 lead coloured black; with the polished surface jet black 

 nearly, shewing very little of the speckled appearance of 

 black granite, except where the surface is wetted. Fracture : 

 irregular and granular, shewing to the lens some minutely 

 lined tabular crystals of Hornblende, and small pearly co- 

 loured splintery crystals of felspar. Structure : much the 

 same as black granite, aggregated, of confused imperfectly 

 fibrous and radiating crystals of a lead colour, mixed with 

 similar crystals of pearly felspar. Structure: something re- 

 sembling that of actinolite : Streak whitish. Infusible by 

 the most intense heat, a few minute specks only intermixing 

 slightly, but becomes whitened : is more brittle than black 

 granite. 



In looking at the pillars of Sultan Tippoo's tomb, I sus- 

 pected at once that they were not made of black granite, 

 from the absence of the speckled appearance. On enquiry 

 I found that no one could point out the quarries from which 

 the stone had been brought ; but I received credible infor- 

 mation, that the Sultan was very fond of it in architecture, 

 and that a considerable quantity had been brought at vari- 

 ous times. I therefore went off, hammer in hand, to examine 

 the Sultan's old palace, long since used as the gun-carriage 

 manufactory, where the fine moulded bases under the wood- 

 en pillars of the Durbar attracted my attention ; and on 

 cleaning one, with a coarse cloth and water, from the dirt 

 and whitewash which coated it, I found it to be formed of 

 the identical stone of the famous pillars. My hammer 

 therefore speedily procured me a specimen, and from the 

 ease and readiness with which it snapped off, I was at once 

 convinced of the correctness of my former guess. I have 

 not been able to identify this rock with any similar one 

 described by authors as having been found in Europe, and 

 Macculloch's definitions are not very precise. Serpentine by 

 Macculloch is not classed as forming a compound rock of any 



