Geology

Geology

By

0
(0 Reviews)
Geology by James Geikie

Published:

1883

Pages:

87

Downloads:

1,597

Share This

Geology

By

0
(0 Reviews)

Book Excerpt

varieties, we shall notice that these three ingredients have each more or less definite crystalline forms; so that they are not distinguished by colour and hardness alone. The metallic-looking substance is mica; the hard gray, or glassy and unscratchable ingredient is quartz; and the remaining material is felspar. The mineralogist's analysis of granite ends here. But there is still much to be learned about quartz, felspar, and mica; for, as the chemist will tell us, these are not 'elementary substances.' Quartz is a compound, consisting of two elements, one of which is a non-metallic body (silicon), and the other an invisible gas (oxygen). Felspar[A] is a still more complex compound, being made up of two metals (potassium, aluminium) and one non-metallic body (silicon), each of which is united to an invisible gas (oxygen). Mica, again, contains no fewer than four metals (potassium, magnesium, iron, calcium) and one non-metallic body (silicon), each of which is in like manner chemica

FREE EBOOKS AND DEALS

(view all)