PLATE VI, 
Figs. 1—10.—Felspathic Minerals and Rocks. 
1. Potash Felspar , primary form, the oblique rhombic prism, as it sometimes occurs at Adula in the Zillerthal, and at 
St. Gothard. 
2. Apple-green Felspar , or Amazon Stone, oblique rhombic prism, with truncation of the acute angles, and double 
truncation of the obtuse lateral edges, from the Urals. 
3. Common Felspar , or Orthoclase , primary form, a horizontal prism, with truncation of all the edges and angles, from 
the Fichtel Mountains. 
4. Adularia , four twins united in the form of a cross, each crystal with truncation of the obtuse angles, from St. 
Gothard. 
5. Socialite , Alike, Peridine, an oblique rhomboidal prism, with truncation of the obtuse lateral and basal edges, and of 
an acute angle, as it occurs in the Zillerthal. 
6. Green Porphyry Felspar ; the primary mass of compact felspar, coloured green by hornblende, contains crystals of 
light-green felspar embedded in it, from Greece, The green porphyry of the ancients. 
7. Black Porphyry, mottled with -white, otherwise of a composition similar to that of the last, from Elfdal in Sweden. 
8. Reel Antique Porphyry, of the same composition, but of a reddish-brown colour, from the quarries of Syene in Upper 
Egypt, frequently used by the ancient Egyptians in the construction of monumental work. 
9. Labrador Felspar, with play of blue and green, polished; the small rhomboidal planes of cleavage are distinctly seen, 
from Labrador. 
10. The same , with play of colours from red to yellow, and from green to blue, polished, from the same locality. 
Figs. 11 — Wr — Micaceous Minerals. 
11. Pennine, or Talcose Mica, an acute rhombohedron, with truncation of the vertex, from Zermatt in Wallis, usually 
dark green. 
12. Common, or Bi-axial Mica, oblique rhombic lamellar aggregations, silver-white, from the granite of Modum in 
Norway. 
13. Black Potash Mica , six-sided table, from Vesuvius. 
14. Ripidolite, or Prismatic Chlorite , a double hexagonal pyramid, with right terminal planes, dark green, from Pfitsch 
in the Tyrol. 
15. Talc, in curved rhombic prisms, with truncation of the acute lateral edges, twisted together in the form of a worm, 
made up of thin 1 ami nay from Piedmont. 
Figs. 16 and 17.— Granite. 
16. Granite, of a medium grain, composed of reddish and white felspar, grey quartz, and black mica, polished from Baveno 
near Mailand. 
17. Red Granite, coarsely granular, consisting of red felspar, grey quartz, and black mica, from the quarries of Syene in 
Upper Egypt, frequently used by the ancient Egyptians in their monuments and more important buildings. 
