July-Ruby

Colour	Red
Formula	Al2O3
Group	Oxides
Uses	Jewellery
Origins	Found in marble and metamorphic rock
Locations	Red Sea, Great Barrier Reef

Ruby is one of the hardest substances and along with sapphire belongs to the corundum group. It's colour is due to the presence of chromium and it may also contain impurities e.g. rutile.

It may often be collected in placer deposits where it is washed up by rivers.