Star Ruby

Star Ruby is a variety of Ruby exhibiting a star pattern, so-called asterism, which is caused by oriented microscopic inclusions, best exhibited in a cabochon cut perpendicular to the c-axis of the crystal.

Asterism is explained by the dispersion and diffraction of inclined beams of light on these oriented acicular inclusions. The sharpness of the star image depends largely on the thinness of inclusions; thinner inclusions produce sharper asterism. It is also possible for inclusions of boehmite, titanite or hematite to cause asterism.

Star Ruby Gemstones by Colour

This table shows the variety of hues this gemstone can be found in. Click on a photo for more information.
 
 
 

Star Ruby Gemstones by Size

This table shows distribution of Star Ruby gemstone sizes that are listed on this site. This can give a good indication as to the general availability of this gemstone in different sizes.
Contributed photos
Lightest:2.00 cts
Heaviest:100.32 cts
Average:18.52 cts
Total photos:19
Do you have a larger Star Ruby? Why not upload a photo?
Significant stones
Eminent Star6,465 cts
Ecce Homo Star Ruby2,890 cts
Rosser Reeves Star Ruby139 cts
2.00ct to 11.83ct11.83ct to 21.66ct21.66ct to 31.50ct31.50ct to 41.33ct41.33ct to 51.16ct51.16ct to 60.99ct60.99ct to 70.82ct70.82ct to 80.66ct80.66ct to 90.49ct90.49ct to 100.32ct
General Information
A variety or type of:Ruby, which is a variety of Corundum
Chemical Formula
Al
 
2
O
 
3
Michael O’Donoghue, Gems, Sixth Edition (2006)
Significant stones
ImageNameWeightCountry of OriginCurrent Owner
Eminent Star6,465.00 ctsIndia
Ecce Homo Star Ruby2,890.00 ctsMozambique
Rosser Reeves Star Ruby138.70 ctsSri Lanka
DeLong Star Ruby100.32 ctsMyanmarAmerican Museum of Natural History
De Long Star Ruby100.32 ctsMyanmar
Edith Haggin de Long Star Ruby100.32 ctsMyanmar
Photos of natural/un-cut material from mindat.org
Physical Properties of Star Ruby
Mohs Hardness9 to 0
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Specific Gravity3.95 to 4.10
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
TenacityBrittle
Michael O’Donoghue, Gems, Sixth Edition (2006)
FractureUneven,Conchoidal
Michael O’Donoghue, Gems, Sixth Edition (2006)
Optical Properties of Star Ruby
Refractive Index1.757 to 1.780
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Optical CharacterUniaxial/-
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
Birefringence0.007 to 0.010
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
ChatoyancyAsteriated (6/12). The chatoyancy is due to oriented microscopic inclusions.
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
Colour
Colour (General)Near colourless through pink through all shades of red to a deep crimson.
Michael O’Donoghue, Gems, Sixth Edition (2006)
TransparencyTransparent,Translucent,Opaque
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
Crystallography of Star Ruby
Crystal SystemTrigonal
Michael O’Donoghue, Gems, Sixth Edition (2006)
HabitHexagonal, rhombohedral
Michael O’Donoghue, Gems, Sixth Edition (2006)
Further Information
Mineral information:Star Ruby information at mindat.org
Significant Gem Localities
Myanmar
 
  • Mandalay Region
    • Pyin-Oo-Lwin District
        • Bernardmyo
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
        • Chaung-gyi
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
        • Kathé (Kathe)
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
        • Kyatpyin Central
          • Baw-lon-gyi (Big Ball)
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
        • Kyauk-Pyat-That
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
          • Yadanar-kaday-kadar
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
        • Marble Ark
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
        • Mogok Valley
          • Dattaw-taung (Dattaw hill)
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
  • Sagaing Region (Sagaing Division)
    • Katha District
      • Wuntho Township
Ted Themelis (2008) Gems & mines of Mogok
Sri Lanka
 
  • Sabaragamuwa Province
    • Ratnapura District
      • Ratnapura
Econ Geol (1981) 76:733-738
Vietnam
 
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