Density: 4.0
Hardness: 9
Varieties: Ruby, Sapphire – Blue, Yellow, Pink, Green
Density: 2.7 to 7.5
Hardness: 7 to 7.5
Varieties: Emerald, Aquamarine – blue to light blue, Morganite – pink, Heliodorus – yellow, Goshenite – colorless.
Density: 3.6 to 4.2
Hardness : 6.5 – 7.5
Varieties: Pyrope – dark red, Almandine – dark red, Grossular – all colors, Spassartite – orange red, Andratite – green to black, Uvarovite – green
Density: 2.65
Hardness : 7
Varieties: Smoky Quartz – light to dark brown, Citrine – yellow, Rock Crystal – colorless, Amethyst – purple
Density: 3.0 to 3.2
Hardness: 7 – 7.5
Varieties: Rubellite – pink, Dravite – black, Elbaite – pink
Density: 3.35
Hardness: 6.5 to 7
Varieties: Tanzanite – blue/purple, Thuilite – pink, Aryolite – green