How do I tell if an emerald has been oiled?

To tell if an emerald has been oiled, look for white or yellow branch patterns along the surface of the gem. If you see them, the gem is likely oiled. Also, examine it under a magnifying glass for any signs of trapped bubbles. These also indicate an oiled gemstone. Consulting a licensed jewelry appraiser is the best way to accurately identify oiled emeralds. You'll find a collection of expertly vetted emerald gemstone jewelry on 1stDibs.