Rubies can have all shades of red.
From a red pink to purple or maroon. Anything but red is sapphire.
Ruby is a matter of the same family as sapphire, corundum.
This is because the amount of chromium and iron in the stone.
Ruby is a durable material with hardness 9 on the Mohs 10-point scale.
But the crystals often grow together and can cause broken material.
In the ruby there may be color zoning, which is because when the ruby formed it's formed in new layer.
Depending on the geological conditions and the variety of minerals are different colors.
Ruby is present throughout the world in Metamorphic rock.
The finest stones come from Myanmar (Burma) but also in Madagascar, Thailand, Vietnam, Norway, etc..
Crystal structure: Trigonal
Composition: Aluminium oxide
Density: 4.00 Refractive index: 1.76 to 1.77