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TRANSACTIONS OF THE 



NINTH ORDER— HARD STONES, OR PRECIOUS 

 STONES OF MOHS. 



H. from 5 1 to 12. 



G. from 2 to 4, 7. 



H. from 5 1 to 7 : opaline, and G. 2, 3 and less; 

 examples — opal, pith, pitchstone and pearl- 

 stone. 



H. from 7 to 8 : G. 2, 3 and less, and opaline, or 

 G. from 3, 4 to 3, 9, and without distinct 

 holoprismatic and diagonal cleavage. 



H. from 8 to 9, without very distinct cleavage, 

 through the basis, the hemidoma, or half 

 bevelment, or the brachy-diagonal, or in two 

 directions, which make an oblique angle. 



When H. does not exceed 8 j : then G. is 4 and 

 less. Examples — Quartz, obsidian, dichroite, 

 tourmaline, axinite, anatase, sphen, brown 

 menac, chrysolite, tautolite, garnet, stauro- 

 lite, zircon, diamond, spinel, beryl, euclase, 

 and topas. 



THIRD CLASS— MINERALS. FIRST ORDER— ORES. 



Metallic lustre, color from gray to black. 



H. from 3 to 9. 



G. from 4, 4 to 8, 5, and not ductile. 



Perfect metallic lustre : H. 7 and more. Exam- 

 ples^ — Octahedral iron ore, Jam, 



