238 



SILICON. 



673. QUARTZ. (Rock Crystal.) 



a. Mass of large crystals. 



b. Mass of smaller crystals. 



c. Rose quartz, massive. 



Note. Specimens 6 and c were presented by Mr. H. Pound. They 

 originally belonged to a collection made by Mr. J. K. Lord. For fig. of 

 the crystals, see Dana, Mineralogy, p. 192. 



PHOSPHORUS. 



674. APATITE. (Native Phosphate of Lime.} 



a. Massive. Two specimens. (Phosphorite.) 



Note. Used in making superphosphate manure, etc. See Dana, Mine- 

 ralogy, p. 530. 



SODIUM. 



675. ALBITE. (Soda Felspar.) 



a. Massive. Two specimens. 



Note. This mineral is a double silicate of aluminum and sodium, with 

 traces of iron, magnesium, calcium, and Potassium. 



676. NATROLITE. (Zeolite.) 



a. In concretions of radiating acicalar crystals. 



Note. This mineral consists chiefly of the silicates of aluminum and 

 sodium, with traces of iron and calcium. See Dana, Mineralogy, p. 426. 



LITHIUM. 



677. LEPIDOLITE. (Lithia Mica.) 



a. Grey variety. Three small specimens. 



Note. Lithia mica contains from one to five per cent, of lithia. For 

 analysis, see Dana, Mineralogy, p. 315. 



678. PETALITE. 



-a. Pink variety. Three small specimens. 

 Note. This mineral contains from two to five per cent, of lithia. See 

 Dana, Mineralogy, p. 229. 



679. SPODUMENE. 



a. Three small specimens. 



Note. Spodumene contains from 4 to 5 per cent, of lithia, sometimes 

 rather more. See Dana, Mineralogy, p. 228. 



SILVER. 



680. NATIVE SILVER. 



a. Crystallized, a small specimen. 



