Colored stones and diamonds - Comparison chart
|
Hardness
|
Toughness
|
Refractive
Index |
|
 - Ruby |
9
|
excellent*
|
1.762-1.77
|
 - Tanzanite |
6-7
|
poor
|
1.691-1.704
|
 - Amethyst |
7
|
good
|
1.54-1.553
|
 - Emerald |
7.5
|
good to poor
|
1.577
|
 - Pearl |
2.5-4
|
usually good
|
1.53-1.686
|
 - Diamond |
10
|
good to excellent
|
2.417
|
 - Sapphire |
9
|
excellent*
|
1.762-1.77
|
 - Blue Topaz |
8
|
poor
|
1.619-1.627
|
 - Tsavorite Garnet |
7
|
fair to good
|
1.760
|
 - Rhodolite Garnet |
7-7.5
|
fair to good
|
1.740
|
|
* Except in twinned stones
|
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© 2010 Au Cornerstone Inc.