Sapphires

Colors - Blue, Yellow, Green, White, Colorless, Pink, Orange, Brown and Purple 
Mohs Hardness Scale - 9
Mineral Class - Corundum


Ruby

Colors - Bright red, brownish-red, purplish-red, dark red 
Mohs Hardness Scale - 9
Mineral Class - Corundum 


Tourmaline

Colors - Black, Red, Pink, Blue, Green, Grey and Yellow 
Mohs Hardness Scale - 7 – 7.5 
Mineral Class - Quartzite 


Garnet

Colors - Light Red, Violet, Red, White, Green, Yellow, Brown, Black 
Mohs hardness scale - 6.5-7.5 
Mineral Class - Quartz 


Alexandrite

Colors - Dark to Pale Green (color is changed in different forms of lights) 
Mohs Hardness Scale - 8.5 
Mineral Class - Chrysoberyl 


Amethyst

Colors - Purple, Pale lavender to deep reddish purple, bluish violet 
Mohs Hardness Scale - 7 
Mineral Class - Quartz


Aquamarine

Colors - Blue, Sea-green 
Mohs Hardness Scale - 7.5 - 8 
Mineral Class - Beryl 


Emerald

Colors - Emerald Green to Dark Green
Mohs Hardness Scale - 7.5 - 8 
Mineral Class - Beryl 


Peridot

Colors - Yellow Green, Olive, Brownish Green 
Mohs Hardness Scale - 6.5 - 7 
Mineral Class - Olivine


Topaz

Colors - Blue, Brown, Green, Orange, Pink, Red, Yellow, White, Gold, Colorless 
Mohs Hardness Scale - 8 
Mineral Class - Topaz