143 
TAB. CCLXXIL 
SILEX talcum. 
Earthy Tale. Green Earth of Veraw. 
Terre verte. 
Class 2. Earths. Order 1. Homogeneous. 
Gen. Silex. Spec. Talcum, 
Div. 3. Amorphous, 
Syn. Green Earth. Kirw. 1. 196. 
Sar to be found near Verona, a3 well as in Bohemia, &c. 
also in Scotland, and Somersetshire. The present specimen 
came from the Hill of Kinnoul in Scotland. It is the largest 
piece I have ever seen, and was lent me by G. B. Green- 
ough, Esq. It is to be found entrapped in a smoothish 
earthy rock in various forms and of different sizes. I 
know not if it could be gathered so pure as to serve for 
commerce there or any where else in Great Britain ; but if 
it could, I should think it might be chosen of such tints as 
might be desirable to artists, it being very durable. It may 
probably be the pigment used in the large draperies often 
exhibited in pictures of the Venetian school, so much ad- 
mired by connoisseurs for their brilliant and lasting greens. 
Mr. Kirwan thought the green colour was owing to a 
mixture of “ Calx of Nickel.” It is not, however, known 
at present what gives permanent colour to most mineral 
substances. Iron in this seems to be particularly oxidated, 
so as to serve that purpose, perhaps with the help of a pe- 
culiar phosphate of a blue colour, mixed with a certain 
