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6.50 carat Koroit Boulder opal 


Stunning Koroit boulder opal with a lightning green and blue fire pattern. Cut round 12mm 


  • Mine - Koroit Boulder
  • Body Tone - Iron Stone
  • Brightness - 5/5
  • Fire colour - Green and blue
  • Size - 12x12x4.5mm
  • Weight - 6.50 carat


About Opals


Treatment: Natural

Luster: Pearly, Vitreous, Opalescence

Birthstone zodiac sign: Libra

Associated month: October

Crystal system: Amorphous solid

Chemical formula: SiO₂·nH₂O

Hardness (Mohs hardness scale): 5.5 – 6.5

Country of origin: Australia, Ethiopia, Mexico and Cornwall amazingly 

Size variations: can vary 0.3mm each way on all dimentions given




In mystical circles, opal is considered a stone representing hope, innocence and purity. It has strong connotations of happiness, faithfulness, loyalty and confidence.  Regarded as a powerful sea stone for safty on the water.


All orders are sent recorded delivery UK and International. 


6.50 carat Koroit Boulder round opal - OPL010

SKU: Opl010
£195.00 Regular Price
£175.50Sale Price
Only 1 left in stock
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