Sapphire

All gem quality corundum that is not red is called sapphire such as blue, orange, yellow, violet, green, white and pink.

Unless a color is stated, sapphire is assumed to be blue. Some sapphires (color change sapphires) will change between blue and violet depending on the light.

Sapphire has a hardness of 9. Generally, sapphire is quite durable. Still, sapphires are subject to chipping and fracture is handled roughly.