NAME. 



^mphibole 

 lomblende. 



COMPOSITION. 



Similar to 

 pyroxene. 



REMARKS. 



USES. 



These minerals occur in many: This also is a very common mineral in 

 igneous rocks, and are generally in igneous and metamorphic rocks, 

 forms without the crystal faces.! 

 See note 5. Also Figures 10 and 12. 



Iron oxide. 

 (Fe203) 



May occur in thin plates or scales This mineral furnishes nine-tenths of the 

 (micaceous), which have a brilliant ore mined in U. S. tcday. Earthy kinds 

 luster. 'are used for red paints. Massive varieties 



Crystals often have an iridescent tar-' nay be ground for a polishing powder 

 nish. The scaly variety seems soft. {(jewelers* rouge). 



'eldspar. 

 ieties are : 

 loclase, 

 lonly in 

 granite) 

 ^oclase 

 includes 

 ral varieties 

 that are 

 similar). 



Aluminium silicates 



of potash, soda and 



calcium. 



Orthoclase is 



( K Al SiSQS) 



Feldspar is the family name for, Used as a constituent of pottery and por- 

 several similar minerals as noted celain. generally in the glaze, but also in 

 under name. The untrained observ-^the body of the ware. . Sometimes used to 

 er cannot separate them so they are'make artificial teeth. Some varieties are 

 grouped together. Feldspar consti-|used for gems, i. e., the moonstone and 

 tutes nearly 60% of the average s unstone. 

 igneous rock, hence it is very abun- 

 dant in igneous and metamorphic 

 rocks. Figures 7, 8 and 19. 



Pyrite. I 



Fool's gold.) i 



igures 1, 2 ' 



and 24. I 



Iron Miliihide. Pyrite occurs in all kinds of rocks 



and with other sulphides. Very 

 common. Often seen in coal. A 

 similar mineral is white iron pyrites, 

 but it requires much experience to 

 distinguish them. 



(iamet. 



Complex calcium, 

 (or) (and) iron (or) 

 (and) magnesium, or 



aluminium silicates. 



Olivine. ; Magnesium, iron sili- 



cate. 

 i (MgFe)=SiO* 



It is burned and the sulphur fumes used 

 to make sulphuric acid. Copper or gold 

 are often found in it and when in suffi- 

 cient amounts it is mined for either one. 



Occurs in isometric crystals in 

 schists, gneisses and crystalline 

 limestone. Several varieties are 

 known and the elements mentioned 

 are variously combined. Fig. 23. 



.\s an abrasive. Thos( 

 color are used as gems 

 stone for January. 



garnets of good 

 It is the birth- 



The hardness, color and mode of 

 occurrence in basalts as rounded 

 grains make this mineral easy to de- 

 termine. 



Sometimes used as a gem. 



Quartz. \ 

 ic various va- 

 ieties of this 

 heral are giv-i 

 en below : 

 *urple var. is 

 the amethyst, [ 

 ■o have milky, 

 se, and smokyi 

 quartz. 



Silicon dioxide. 

 <.Si02) 



iWhen crystallized has a 6-sided 

 pyramid on the end of 6-sided 

 nrism. Keep in mind its hardness, 

 luster, fracture and form as the best 

 determinative features. See Fig. 17. 



rail-parent to 

 ^trcin-lucent ; 



:edony. ' 

 lalcedony] 

 : nelian : | 

 . with red 

 - is the 

 1 -idstone, 

 .hstone for 

 March, 

 jded, with 

 lous colors, 

 agate, 

 onyx the 

 anas are 

 traight. 



Si02 



Gems, abrasives (for sand paper, grind- 

 stones, etc.). In form of sand used for 

 glass making ; in mortars and cements ; as 

 refractory material. Rock crystal is used 

 by some people for "crystal gazing." 



Quartz either as the crystalline va- 

 riety, or compact kind, is found 

 everywhere. It forms the sand 

 dunes and sandstones. It is found 

 in veins with the valuable metals. 

 It is an essential constituent ot 

 granite and is found in many other] 

 igneous rocks. Flint and chert are 

 found in chalk and limestone in 

 formj of nodules. When silicon 

 dioxide contains water it does not 

 crystallize and is known as the 

 opal. 



.\gates and moss agates are known to every 

 school-boy. They are also widely used as 

 ornaments. Onyx is used for making 

 cameos. Flint, chert, etc., are crushed 

 and used as road-making materials. 



32; 



