Ruby is the birthstone for July and the gem for 40th Wedding Anniversaries. Desired throughout history, it is available in deep red to lighter vibrant red, its hardness is 9 on Mohs hardness scale. Fine quality Ruby is becoming increasingly rare especially in gems over 1ct. Due to the shape of the crystal Ruby is usually cut into oval and cushion shapes, so large rounds, squares and emerald cuts are scarce. Bright clean gems are desirable, dull included material is unattractive. Very poor, fractured material is glass filled to make it saleable, this Glass Fracture Filled Ruby is very inexpensive and the treatment must be disclosed. Country of origin does not guarantee fine quality as all areas produce various qualities. Ruby is currently mined in Mozambique and Madagascar, with limited quantities from Burma, Sri Lanka, Tanzania, Thailand and Vietnam also supply small amounts of Ruby. A rare variety of Ruby which contains dense intersecting silk needles may display a 6 ray star when cut as a cabochon. Fine quality Star Ruby is very rare, poor quality star Ruby is dyed to improve the colour to a purplish red, this process must be disclosed. Rubies specific gravity is 3.80 – 4.05 and the refractive index is 1.760 -1.778, doubly refractive.