100 BULLETIN 118, UNITED STATES NATIONAL MUSEUM. 



Table, rectangular girdle; violet; 1.355 carats; 7 by G by 4 mm No. 001 



Table, square girdle; deep blue-green; 1.35 carats; 7 by 4 mm No. 600 



Step-brilliant, elliptical girdle; violet; 1.178 carats; 7 by 6 by 4 mm No. 597 



Step-brilliant, square girdle; dark violet; 1.036 carats; G by 4 mm No. 598 



Cabochon, circular girdle; deep red; 1.01 carats; 6 by 3 mm No. 603 



Step-brilliant, rectangular girdle; dark green; 0.955 carat; 7 by 5.5 by 3.5 mm. No. 615 



Step-brilliant, circular girdle; red-violet-brown; 0.92 carat; 6 by 3 mm No. 620 



Table, rectangular girdle; ligbt violet; 0.918 carat; 7 by 5 by 3 mm No. 602 



Step-brilliant, rectangular girdle; orange-red; 0.83 carat; 6 by 5 by 4 mm. . . No. 616 



Step-brilliant, square girdle; deep rose-red; 0.7 carat; 5 by 3 mm No. 617 



Step-brilliant, elliptical girdle; dark red-violet; 0.635 carat; 6 by 5 by 3 mm. No. 618 



Brilliant, circular girdle; blue-violet; 0.575 carat; 5 by 3 mm No. 619 



Cabochon, circular girdle; bright red; 0.467 carat; 5 by 3 mm No. 604 



Step-brilliant, square girdle; deep red; 0.435 carat; 5 by 3 mm. Isaac Lea 

 collection No. 605 



EAST INDIES. 



Polished pebble; deep red; 9.1 carats; 13 by 11 by 7 mm No. 622 



Polished pebble; deep red; 5.3 carats; 10 by 8 by 7 mm No. 623 



Polished pebble, pear-shaped; deep red; 4.66 carats; 12 by 8 by -5 mm No. 625 



Polished pebble; deep red; 4.58 carats; 10 by 9 by 5 mm No. 624 



Polished pebble; deep red; 3.79 carats; 10 by 7 by 5 mm No. 627 



Polished pebble; deep red; 2.9 carats; 10 by 7 by 4 mm No. 626 



Table, rectangular girdle; deep red; 2.815 carats; 8.5 by 7 by 4 mm No. 621 



Polished pebble; deep red; 1.88 carats; 9.5 by 8 by 2.5 mm No. 628 



Polished pebble; deep red; 1.72 carats; 8.5 by 5.5 by 3.5 mm No. 629 



SPODUMENE. 



Varieties. — Hiddenite and kunzite. 



Composition. — Lithium aluminum metasilicate, Li, Al (Si0 3 ) 2 . The 

 variety hiddenite carries a little chromium, to which it is thought its 

 color may he due. 



Crystallization. -Monocluric; prismatic. 



Color. — White to yellow, rarely amethystine. Hiddenite, yellow 

 green to emerald green; kunzite, pale pink. 



Luster. — Vitreous, transparent to translucent. 



Hardness. — 6.5 to 7. 



Specific gravity. — 3.13 to 3.20. 



Optical properties. — Refractive index, 1.66; pleochroism strong. 



Hiddenite, or lithia emerald, is a variety of spodumene varying 

 in color from a yellow-green to a deep emerald-green tinged with 

 yellow, the colors of the crystal usually being yellow at one extremity 

 and a more or less deep green at the. other. The deeper colored kinds 

 afford a gem resembling the emerald, hut having a greater variety 

 cf color because of its strong pleochroism. The mineral occurs in 

 slender prismatic er}-stals one-half inch to 2 inches in length, afford- 

 ing small gems only, the largest being under 3 carats in weight. 

 Hiddenite is at present known from hut one locality, Stony Point, 

 Alexander County, North Carolina, where it is found in metamorphic 



