538 



REPORT OF NATIONAL MUSEUM, 1900. 



III. (hmparative tahlen oj the rolorx and disllnguinhimj characters of the belter- fcnotvn 



ijems — Continued. 



Name. 



Zircon (jacinth). 



Sapphire (orien- 

 tal topaz). 



Garnet (topazo- 

 litc or grossn- 

 larite, also es- 

 sonite or cin- 

 namon stone). 



C h r y s o b e r y 1 

 (o rlental 

 chrysolite). 



Spinel . 



Topaz 



Diamond 



Olivine (chryso- 

 lite). 



Tonrmaline 



Beryl . 



Quartz (citrine 

 or Scotch, 

 Spanish, Sax- 

 on, or false 

 topaz). 



II.— YELLOW STONES. 



Specific 

 gravity. 



3.97-1.2' 



3. 5 -3. .S9 



3. 48-3. .52 

 3. 33-3. 5 



2. 73-2. 76 

 2.55-2.7 



Hardness. 



7.5. Harder 

 than quartz. 



'^. Scratches all 

 other stones of 

 the group ex- 

 cept diamond. 



6.-5-7.5. Varies, 

 but majority of 

 specimens will 

 scratch quartz 

 slightly. 



S.5. Scratched 

 by sapphire; 

 scratches a 1 1 

 others except 

 diamond. 



8. Scratched by 

 diamond, sap- 

 phire; scratch- 

 es quartz. 



do 



6-7. Scratched 

 by quartz. 



7-7.5. But little 

 harder than 

 quartz. 



7.5-8. Specimens 

 vary. 



7 



Refraction and 



refractive 



index. 



Double, strong- 

 ly so. 1.990. 



Double. 1.765. 



Single. 1.759., 



Double. 1.760. 



Single. 1.755 

 to 1.810. 



Double. 1.635. 



Single. 2.455. 

 Double. 1.660 



Double. 1.625 



Double; weak. 



1.585. 

 Double. 1.549 



Disper- 

 sion. 



.025 



Distinguished from quartz 

 in that its luster is dulled 

 by strong hydrochloric 

 acid; also by its higher 

 specific gravity, and 

 from all others of the 

 group by hardness and 

 specific gravity. 



Distinguished by its hard- 

 ness and specific gravity. 

 Becomes electrified by 

 friction. 



The yellow is tinged with 

 green. Acquires elec- 

 tricity by friction. Dis- 

 tinguished by its hard- 

 ness,specific gravity and 

 peculiar yellow color. 



Distinguished by its spe- 

 cific gravity and hard- 

 ness. Does not become 

 electrified by friction. 



Distinguished from spinel 

 by its electrical proper- 

 ties, and from other 

 stones by its hardness 

 and specific gravity. 



Readily distinguished by 

 its hardness. 



The yellow is tinged with 

 green. Distinguished by 

 its hardness and specific 

 gravity. 



Becomes electrified by 

 friction; one extremity 

 of crystal -I-, other — . 



