SPECIFIC GRAVITY OF GEMS. 



Tab'e of Specific Gravities — continued. 



407 



Quartz (silica) — 



Rock crystal 



(F. W. Clarke gives a range from 



2-61 to 2-6507) 

 Amethyst 



(F. W. Clarke gives a range fi'om 



2-659 to 2-744) 



Rose quartz (2 specimens) 



(F. "W. Clarke gives a range from 



2 651 to 2-6 8) 

 Cairngorm 



(F. W. Clark" dives a range from 



2-fi51 to 2-')58, smoky) 

 Fibrous quartz '"catseye") 



Opal hydrous silica (2 specimens) 

 *' flawed 



Spinel (magnesium aluminate) — 

 Spinel, dark blue 



" puce 



" dark puce 



(F. W. Clarke gives a range from 

 3-48 to 3-77) 



Topaz (aluminium silico-fluo- 



lide)— 

 Topaz, colorless 



•white (2 specimens) 



yellow Brazilian 



pink HraziUan, burnt. 



(F. W. Clarke gives a range from 

 3-439 to 3-597) 



Tourmaline (aluminium boro- 

 silieate) — 



Tourmaline, brown 



(F. W. Clarke gives a range for 



brown Tourmaline Irom 3-035 



to 3-068) 



TuRaroisK, (hydrous aluminium 



phosphate) 

 (F. W. Clarke gives a range from 

 2-426 to 2-651) 



Zircon (zirconium silicate) — 

 Zircon, red 



" cut and polished 



" pale green 



(F. W. Clarke gives a range from 

 4-047 to 4-709 at 2P C.) 



