Ruby and Sapphire (corundum)

Ruby and Sapphire

Chemistry:

Aluminum oxide - Al2O3

Crystal system and habit:

Trigonal: Hexagonal prisms with basal pinacoid or hexagonal bipyramids.

The triangular markings on the pinacoid. Also commonly occurs as water worn pebbles.

Two crystal habits are most typical in the rubies and sapphires

Ruby crystals 

Varieties: Transparent to opaque.

·    Colorless Sapphire: pure corundum is colorless (or nearly so).

·    Ruby: red

·    Blue Sapphire: blue, violetish blue to greenish blue..

·     Fancy Sapphire: colors other than red or blue are named as fancy sapphire for example Pink, green, yellow, orange, pinkish orange ( PADPARADSCHA).

Phenomena:

Star Ruby and Star Sapphire (Usually 6 rays, sometimes 12). Color-changing sapphire.

Cleavage                   :                      Present (False parting)

Furacture                   :                     Concodial

Hardness                   :                     9

Refractive index       :                      1.762 to 1.770 mostly

Birefrigence              :                      .008

Pleochrosim              :                       Ruby strong, Sapphire moderite

Luster                         :                       Vitrious

Specific Gravity                                 3.92 to 4

 

Occurrence:

   Ruby: 

Burma, Thailand, Sri Lanka, Vietnam, Kenya, Tanzania, Kampuchea, Afghanistan, India, Pakistan

Sapphire: 

Kashmir, Sri Lanka, Burma, Thailand, Australia, Kenya, Tanzania, USA, Madagascar.

Yellow Sapphire: 

Sri Lanka, Thailand, Australia, Tanzania.

·       Purple Sapphire:

     Sri Lanka, Tanzania.

·       Green Sapphire: 

     Australia, Sri Lanka.

·       Star Stones: Burma:

     Sri Lanka, Thailand, India, Australia, Kampuchea.

 

violetish blue sapphire from Basil area, Kashmir, Pakistan 

purplish pink sapphire from Basil area, Kashmir, Pakistan