Image: Facetted Fire Opal #13769, 16,3x16,0x10,8mm cushion, 12,54cts.
The second important source for precious opal, besides Australia, is Mexico. This variety of opal can be found in cavities and cracks of volcanic deposits. It exists from colorless, over shades of yellow and orange ranging to an intense red – depending on the amount of iron oxide.
Only very small amounts of the Fire Opal rough material show play-of-color. Because of this rarity the play-of-color stones are way more expensive than the unicolored ones.
Finds of Fire Opal, especially in good qualities got very rare over the last years. Clean material with no play-of-color is mostly used to cut facetted stones to optimize the brilliance. The very rare Mexican Fire Opals with play-of-color are normally cut as cabochons or Freeshapes.