CATALOGUE OF GEMS AND PRECIOUS STONES. 213 



VII. Color red or pink — Continued. 



A. Transparent or nearly so — Continued. 



(b) Hardness 8 to 7; scratched by corundum but not by quartz. 



1. Sp. gr. high, 3.9; color intense red; isotropic Garnet, pyrope, (etc.). 



2. Sp. gr. fairly high, 3.6; color intense red; isotropic Spinel, balas-ruby. 



3. Sp. gr. fairly high, 3.5; color orange-red to pink; anisotropic Topaz. 



4. Sp. gr. fairly high, 3.1, colorpink; pleochroism strong.. Tourmaline, rubellite. 



5. Sp. gr. medium, 2.7; color pink: pleochroism faint Beryl, "morganite." 



(The rare pink grossularite garnet and the red variety of zircon belong 

 here.) 



(c) Hardness less than 7; scratched by quartz. 



(The little used mineral piedmontite, and the rare red-colored varieties 

 of amber, and pink-colored varieties of fluorite and spodumene-kunzite 

 belong here; also opal and artificial glass.) 



B. Opaque or nearly so. 



(a) Hardness greater than 6; scratch microcline. 



1. Sp. gr. fairly high, 3.3; color dull red or violet red Zoisite, thulite. 



2. Sp. gr. medium, 2.6; color pink, cloudy Quartz, rose. 



3. Same, but color red Chalcedony, carnelian. 



4. Same, but more opaque Chalcedony, jasper. 



5. Same, but banded Chalcedony, agate. 



(6) Hardness less than 6; will not scratch microcline. 



(The little used minerals lepidolite, rhodonite, and rutile belong here : 

 also coral and artificial glasses.) 

 VIII. Color black. 



(a) Hardness 9 or greater; not scratched by corundum. 



(Black diamond or carbonado belongs here; it scratches corundum.) 



(b) Hardness 8 to 7; scratched by corundum but not by quartz. 



1. Sp. gr. 2.7 Quartz, smoky. 



2. Same, more opaque; artificially colored Chalcedony. 



3. Same, banded Chalcedony, agate. 



(The rarely used black varieties of spinel and tourmaline belong here.) 



(c) Hardness less than 7; scratched by quartz. 



1. Sp. gr. very high, 5.3; "streak" (powder) red Hematite. 



2. Sp. gr. medium, 2.5; glassy Obsidian. 



3. Sp. gr. medium; glassy Glass (artificial). 



4. Sp. gr. low Jet (and coal). 



(The little used minerals allanite, chromite, gadolinite, ilmenite, mag- 

 netite, rutile, and samarskite belong here.) 

 Possessing internal colors: 

 A. Transparent or nearly so. 



(a) Hardness 9 or greater; not scratched by corundum. 



1. Does not scratch corundum surface; int. refl. silvery, 6-rayed. 



Corundum, asteria. 



(b) Hardness 8 to 7; scratched by corundum but not by quartz. 



1. Sp. gr. 2.7; int. refl. silky, forming fine sharp line.-.Chrysoberyl, cat's-eye. 



2. Sp. gr. 2.7; int. refl. silky, forming broad band Quartz, cat's-eye. 



(The rare tourmaline-cat's-eye belongs here.) 



(c) Hardness less than 7; scratched by quartz. 



1. Sp. gr. medium, 2.6; int. refl. blue to silvery- white. . .Feldspar, moonstone. 



2. Sp. gr. rather low, 2.2; int. refl. various brilliant colors Opal. 



(Some amber, feldspar variety sunstone, obsidian, and various kinds of 

 artificial glass belong here.) 



