CATALOGUE OF GEMS. 495 



CATLINITE. 



PIPE STOXE. 



Catlinite, or pipe stone, is a compact clay slate of an ash g'ray to 

 deep red color, or red with white and gray spots. It occurs in beds 

 in Pipestone, especially at Coteaii de Prairies, and in Cottonwood, 

 Watonwan. Nicollet counties, Minnesota; at Flandeau and Sioux 

 Falls. South Dakota; Sac County, Iowa; Barron County, Wisconsin, 

 and elsewhere in the Upper Mississippi and Missouri country. Cat- 

 linite is worked into ornamental pipes, paper weights, ash trays, 

 match boxes, and other trinkets. 



CAT'S-EYE. 



The term cat's-eye is applied to a lumiber of minerals which, when 

 cut cabochon, exhibit a peculiar opalescence characterized by a line, 

 or ray, of light across the stone and resembling- the contracted pupil 

 of the eye of a cat. Among the minerals which, when fibrous or cut 

 across the cleavage, will show the cat's-e3^e ra}' are: Ber}'!; chryso- 

 l)eryl, especiall}^ the cymophane; corundum; crocidolite; dumortier- 

 ite; quartz filled with acicular crystals or fibrous minerals, such as 

 actinolite, Iwssolite, hornblende, etc.; h3'persthene; enstatite: bronz- 

 ite; aragonite; gypsum; labradorite; limonite; hematite, etc. Such 

 gems may be opaque, translucent, or transparent, and raa}^ be of any 

 color or colors. 



CHONDRODITE. 



The hardness, translucency, and range of color of this mineral ren- 

 der it suitable for use as one of the minor gems. It occurs in mono- 

 clinic crystals of a varied habit; also massive, compact, and in 

 embedded grains. Its hardness is 6.5; brittle. Cleavage indistinct. 

 Fracture conchoidal. Luster, vitreous. Specific gravity, 3.1 to 3.2. 

 Color, light to dark yellow, honey yellow, garnet, hj^acinth, and brown- 

 ish red. Pleochroism occasionally distinct, especially in brownish-red 

 cr3'stals. 



Chondrodite, from jot'fjpocr, a grain, in allusion to its granular 

 structure, occurs usually in embedded grains or granular masses in 

 limestone. It is found abundantl}^ at the Till}^ Foster mine, Brew- 

 ster, New York, in deep garnet-red crj^stals of great beauty. 



One hundred parts contain approximateh" Silica, 33.06; magnesia, 

 5.5. -±6; iron, 3.65; fiuorine, 7.60. 



CHRYSOBERYL. 



AI.KXAXDRITE^ — CAT's-EYE CVMOPnANE. 



The gems known as ah^xandrite, oriental chrysolite, and cymophane, 

 or true cat's-eye, are varieties of chrvso})eryl. Th(^ minei'al crystal- 

 lizes in the orthorhombic system, generally in ta])ular crystals, often 



