CATALOGUE OF GEMS. 515 



LEPIDOLITE. 



Lithia mica is used to some extent for ornaments, such as ash trajT's, 

 dishes, vases, paper weights, etc. The colors range from rose pink 

 through a variety of shades of violet gray to yellowish and whitish. 

 It occurs in granular masses made up of foliated scales. Hardness 

 about 4; specitic gravity, 2.84 to 3. 



MAGNETITE. 



LODESTONE. 



Lodestone, a magnetite that possesses polarity, is worked up into 

 charms and worn soleh' for the mystic properties it is supposed to 

 possess. Color, iron black; luster, metallic; hardness, 6.4; specific 

 gravity, 5. Brittle, opaque, strongly magnetic, and possessing 

 polarity. 



Composition: Iron, 72.4; oxygen, 27.6. 



MICROCLINE. 



AMAZONSTONE A V EXTURIXE. 



]\Iicrocline, one of the feldspars, occurs massive and in triclinic 

 crystals, resembling those of orthoclase, common feldspar, in habit. 

 Its hardness is 6.5; specific gravity, 2.54; cleavage perfect and in two 

 directions; luster, vitreous; translucent to opaque, and varying in 

 color from white to pale cream yellow, red, and green. 



Two recognized varieties are used either as gems or ornamental 

 stones. 1. Amazonstont^ a green-colored microcline. Its color range 

 includes the several shades of green, from the palest and most delicate 

 to a strong, deep, verdigris green. (Plate 3.) 2. Aveixturine^ consist- 

 ing of interlaminatedalbite and microcline, and often including dissem- 

 inated scales of hematite or gothite, giving rise to internal yellowish 

 or reddish reflections. 



Microcline contains in 100 parts: Silica, 64.7; alumina, 18.4; potash, 

 16.9. 



MICROLITE. 



Occasionally crystals of microlite are found that are sufficiently 

 transparent to aflord gems ranging in color from cinnamon brown to 

 orange red and spinel yellow. The hardness of the mineral is 5.5; 

 specitic gravit}", 5.65 to 6.13, greater than that of any other known 

 gem, luster, resinous to vitreous, transparent to translucent and 

 opaque. 



In composition it is essentially a tantalate of lime. 



