RUBY
the red variety of corundum

VARIETY INFORMATION:

  • VARIETY OF: Corundum , Al2O3 .
  • USES: Gemstone.
  • BIRTHSTONE FOR: July
  • COLOR: various shades of red.
  • INDEX OF REFRACTION: 1.76 - 1.78
  • BIREFRINGENCE: 0.009
  • HARDNESS: 9
  • CLEAVAGE: none, although there is a rhombic parting
  • CRYSTAL SYSTEM: trigonal
  • PLEOCHROIC: strongly
  • For natural ruby mineral specimens see our For Sale or Sold lists

Ruby is the red variety of corundum, the second hardest natural mineral known to antiquity. The non-red variety of corundum is Sapphire. Sapphires are well known among the general public as being blue, but can be nearly any color. The red color in ruby is caused by trace amounts of the element chromium. The best shade of red for ruby is often given the name "pigeon blood red", but ruby can be any shade of red up to almost pink.

Oriented rutile crystal inclusions cause a six-rayed-star light effect (called asterism) to form the popular Star Ruby.

Rubies come from all over the world but good gemstones are found at Thailand, India, Madagascar, Zimbabwe, North Carolina in the U.S., Afghanistan, Pakistan, Sri Lanka, Kenya, Tanzania, Kampuchea, and perhaps most notably, Burma.

Rubies have a famous place in science - the first lasers were made from artificial ruby crystals.  They still are used for this purpose although other materials offer improved efficiency.  Some ruby crystals show the fluorescence (actually very short term phosphorescence) that makes a laser possible.

This Site Awarded
Available RUBY specimens:
RUBY specimen RUB-52
$ 45.00 -50% = $ 22.50
Dims: 1.89x1.55x1.49in (4.80x3.94x3.77cm) .... Wt: 5.1oz (144g) .... Loc: Madagascar
The cross-section of this sapphire crystal shows good hexagonal form and most of one natural termination. Part of the specimen is a mass of brown to black muscovite plus minor amounts of albite.
no photo
RUB-52
$ 22.50
no photo
RUBY specimen RUB-48
$ 25.00 -20% = $ 20.00
Dims: 0.88x0.84x0.64in (2.22x2.14x1.62cm) .... Wt: 0.40oz (11.3g) .... Loc: Rai-Iz, Polar Ural, Russia
This small specimen contains four ruby crystals, but only one is significantly exposed - the others show a single face. Still, it is a nice ruby crystal, with excellent color and a pleasing appearance when examined using a loupe.
no photo
RUB-48
$ 20.00
no photo
see this List of ALL specimens including SOLD ones

 

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