12 PHYSIOGRAPHY. 



Amblygonite. 



na and other countries. It has repeatedly been met with in various parts 

 of the Green sand formation of the United States, either loose in the soil, 

 or engaged in marl or lignite, as at Gay Head on Martha's Vineyard, 

 near Trenton in New Jersey, at Camden in Pennsylvania, and at Cape 

 Sable (near Magothy river) in Maryland. 



6. The more transparent and handsomely colored specimens are cut 

 into various ornaments and works of art ; more common varieties are em- 

 ployed in the formation of certain kinds of varnish. It is also used for 

 fumigation. The oil and acid of amber were formerly articles of medi- 

 cine. 



AMBLYGONITE. Prismatoidal Petaline- 

 Spar. 



Primary form. Oblique rhombic prism. M on M' = 

 106 10'. 



Cleavage parallel to the prismatic faces, apparently with 

 greater facility in one direction than in the other. Frac- 

 ture uneven. 



Lustre vitreous, inclining to pearly. Color greenish- 

 white, passing into light mountain and celandine-green. 

 Streak white. Semi-transparent . . . translucent. 



Hardness = 6-0. Sp. gr.^3-00 . . . 3-04. 



Compound Varieties. Massive : composition columnar. 



1, Heated by itself in a matrass, it affords a little moisture, which in a 

 high heat is perceptibly acid, and corrodes the glass. Upon charcoal, 

 before the blow-pipe, it easily melts into a clear glass, which however 

 becomes opake on being suffered to cool. 



2. Analysis. 

 By BERZELIUS. 



Phosphoric acid . , . . 54-12 

 Alumina .... 38'96 



Yttria .... 692 



3. It is found only at Chursdorf near Penig in Saxony, where it occurs 

 in granite along with Tourmaline and Topaz. 



AMETHYST. (See Quartz.) 



