10 Cool Facts About September’s Birthstone, Sapphire!

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Logan SapphireFrom the mountains of Montana to the island of Madagascar to Thailand, Burma and Eastern Australia, sapphires of different colors and grades are mined year-round.  Some wind up beautifully faceted to adorn your body as jewelry, while others that are not gem quality find practical use as insulating electronic wafers in solid-state electronics, in wristwatches as movement bearings and crystals as well as in enhanced-durability windows and other uses.

If sapphire is your birthstone or if you just love the beauty of this precious gem, here are 10 cool facts about sapphire that you may not know…

  1. Sapphire is the third hardest mineral on the Mohs Scale with a hardness of 9.  Diamond is the hardest known mineral with a hardness of 10, while Moissanite is second at 9.5.
  2. Sapphires are used to make optical windows for uses as far ranging as UV & IR detectors to gas/air analyzers to bar code readers.
  3. Sapphires and rubies are varieties of the same mineral, corundum.  The only difference is color.  Rubies are always red.
  4. All colored varieties of corundum (except for rubies) are considered sapphires
  5. The red color of rubies is caused by chromium impurities in corundum, while the variety of sapphire colors is caused by various impurities in the corundum mineral including iron, titanium and smaller amounts of chromium (pink sapphire).  Beware of what some markets refer to as “light rubies,” as these are pink sapphire and, while beautiful, are not considered as valuable as real rubies.
  6. Oddly enough, especially given the specifics of #5 above, there are actually no concrete rules regarding what shade of red determines a ruby and what shade of pink determines a sapphire…which creates a grey area between “light rubies” and sapphires.  Confused?  Yep, so are we.  CF Brandt eliminates the grey area…our rubies are rubies and our sapphires are sapphires.
  7. The Blue Giant of the Orient is the world’s largest faceted blue sapphire, weighing in at 466 carats.  The second largest is the Logan Sapphire at 423 carats.
  8. Sapphires are the modern birthstone of September, while it was the classic birthstone of April.  The sapphire is the stone of sincerity, as it Star Sapphireassociated with honesty, faith, divine understanding and blessings.
  9. As well as eye-catching colors from pink to blue to green, sapphires also come in black, grey and clear/white.  The clear/white variety can be confused with diamonds and is actually sometimes used as a diamond substitute.
  10. Star sapphires feature a reflective 6-point star shape when shaped and polished rather than faceted.  The reflective star is caused by tiny needle-like inclusions, typically of the titanium-rich mineral rutile.  In some very rare occurrences, inclusions of hematite platelets cause additional reflection that results in a 12 point star.