Corundum

  

Sapphire twin on sapphire

  

 

  

Origin: Ratnapura, Sri Lanka

Sample size: 3 x 2 x 1.2 cm (top), 4.5 x 2 x 1.2 cm (2nd/3rd row), 2.1 x 1 x 1 cm (4th/bottom row)

 

Ruby on marble

Origin: Jagdalek, Afghanistan

Sample size: 2 x 1.3 x 1.2 cm

 

  

  

This specimen features a 3.5-cm-long doubly terminated crystal perched smartly on matrix, with an adjacent fatter crystal. These corundums are generally called sapphires on the market but to me, I cannot decide which to label them as. They go varying shades of red/purple and even to blue-purple depending on which lighting source you use to look at them. The effect is not subtle, either - its pretty obvious. These pics were taken under both fluorescent and halogen lights to show the colour change.

Origin: Amboharony, Ihosy, Madagascar

collected by Dr. Federico Pezzotta

Sample size: 10.3 x 4.7 x 4.2 cm

 

Photo courtesy of: 

Rob Lavinsky

The Arkenstone

 

Photo courtesy of: 

 

5 mm large grey corundum crystals in gneiss matrix

Origin: Miassovo, Ural, Russia

Sample size: thumbnail

 

Gray crystalline corundum in pegmatite matrix

Origin: Karathupalayam, Silvamalai, Coinbatore district, Tamul Nadu, India

Sample size: 3 x 6 cm

 

Photo courtesy of: 

 

  

  

Sapphire in mica schist

Origin: Camp Creek Mine, Montana, U.S.A.

Ex. Keith Hayes collection

Sample size: 9.9 x 6.5 x 2.5 cm

 

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