618 REPORT OF NATIONAL MUSEUM, 1900. 



Moss agate, see Quartz. 



Obsidian. Yellowstone National Park. Color, brown, with black blotches. Two 

 pieces of ecjual size. Cabochon cut; elliptical girdle. Size, 26 by 19 by 6 mm. 

 Cat. Nos. a-682-683; 46825. TheU. S. Geological Survey. 



Obsidian. Yellowstone Park. Color, brown. Cabochon cut; circular girdle. Two 

 pieces, each 25 mm. diam., 10 mm. thick. Cat. Nos. a-684-685; 46825. The 

 U. S. Geological Survey. 



Obsidian. Yellowstone National Park. Color, brown, with black blotches. Cabo- 

 chon cut; rectangular girdle. Two pieces, each 22 by 18 by 10 mm. Cat. Xos. 

 a-686-687; 46825. The U. S. Geological Survey. 



Obsidian. Yellowstone National Park. Color, dark brownish black. Cabochon 

 cut; rectangular girdle. Two pieces; respective sizes, 28 by 21 by 7 mm., 35 by 

 19 by 6 mm. Cat. Nos. a-688-689; 46825. The U. S. Geological Survey. 



Obsidian. Yellowstone National Park. Color, black. Elliptical disks. Two pieces, 

 each 21 by 17 by 3 mm. Cat. Nos. a-690-691; 46825. The U. S. Geological 

 Survey. 



Obsidian. Yellowstone National Park, Wyoming. Color, smoky black. Cabochon 

 cut; elliptical girdle. Cat. Nos. a-692; 48925. Gift of Dr. Robert H. Lamborn. 



Obsidian, var. moldavite. Moravia. Color, dark green. Step-brilliant cut; ellipti- 

 cal girdle. Size, 24 by 17 by 11 mm.; weight, 22.55 carats. Cat. Nos. a-693; 

 45119. 



Obsidian, var. moldavite. Moravia. Color, dark green. Brilliant cut; rectangular 

 girdle. Size, 13 l)y 10 by 7 mm; weight, 4.83 carats. Cat. Nos. a-694; 45119. 



Oligodase. Hawk mica mine, near Bakersville, Mitcliell County, North Carolina. 

 Colorless. Step-brilliant cut; rectangular girdle. Size, 14 by 10 by 6 mm.; 

 weight, 5.90 carats. Cat. Nos. c-279; 50103. 



Oligoclase. Hawk mine, near Bakersville, Mitchell Coufity, North Carolina. Color- 

 less. Brilliant cut; square girdle. Size, 8.5 by 6 mm.; weight, 2.35 carats. 

 Cat. Nos. c-230; 48470. 



Oligoclase. Norway. Color, dark gray, with change of color. Cabochon cut; 2 

 elliptical, 1 square girdle. Sizes, 20 by 12 by 7 mm., 14 by 10 by 4.5 mm., 11 

 by 4 mm. Cat. Nos. a-281-283; 84183. 



Oligoclase, var. moonstone. Delaware County, Pennsylvania. Color, light gray. 

 Diamond shaped. Size, 54 by 30 by 17 mm. Cat. Nos. c-294; 84185. Gift of 

 Charles Wilkes, U. S. N. 



Oligoclase, var. moonstone. Colorless. Cabochon cut; rectangular girdle. Size, 22 

 by 10 by 7 mm. Cat. Nos. c-295; 50276. 



Oligoclase, var. sunstone. Arendal, Norway. Color, brown. Cabochon cut; circu- 

 lar girdle. Two pieces. Size, 23 by 5.5 mm. Cat. Nos. c-269-270; 50332. 



Oligoclase, var. sunstone. Krageroe, Norway. Color, reddish. Size, 8 by 5 by 2 

 cm. Cat. Nos. b-862; 84227. 



O^odasc, var. sunstone. Norway. Color, reddish brown. Cabochon cut; elliptical 

 girdle. Five stones. Average size, 14 by 11 by 5.5 mm. Cat. Nos. c-271-275; 

 82850. The Lea Collection. 



Oligoclase, var. sunstone. Norway. Color, reddish brown. Double cabochon cut; 

 elliptical girdle. Size, 14 by 11 by 5 mm. Cat. Nos. c-276; 83528. Lea Collec- 

 tion. Gift of Dr. L. T. Chamberlain. 



Oligoclase, var. sunstone. Norway. Color, reddish brown. Cabochon cut; rectan- 

 gular girdle. Size, 32 by 9 by 3 mm. Cat. Nos. c-277; 84182. 



0/i5roda,se, var. moonstone. Ceylon (?). Colorless. Cabochon cut; elliptical girdles. 

 Seven gems. Size of largest, 21.5 by 9 by 4 mm. ; average of remainder, 7 by 4 

 by 3.5 mm. Cat. Nos. c-4] 0-416; 84186. 



Oligoclase, var. moonstone. Floitenthal, Tyrol. Colorless. Cabochon cut; ellip- 

 tical girdle. Size, 22 by 14 by 7 mm. Cat. Nos. c-417; 84187. 



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