Identifying Inclusions Found in Synthetic Gems

Curved Striae

Flame fusion grown corundum are the most common synthetics. They come in a variety of colors, are very durable, and exceptionally inexpensive to manufacture.

If, when examining a gem your RI indicates corundum, your next step is to distinguish if it is natural or synthetic. Your first clue that the gem you are examining is a synthetic is poor workmanship. Cheap synthetic rubies and sapphires do not get the care a precious gem does. A clean interior, with no crystal or silk inclusions, is your next clue.

With diffused lighting, look for curved or straight growth lines. Curved lines are difficult to distinguish, because the curvature is very subtle. The first picture shows curved striae on the pavilion main facets of an emerald cut gem. However, you may not see this much. The second picture shows a partial view of the curved striae. It takes practice to make this distinction. Once recognized, you are certain that the gem is a flame fusion synthetic.

Synthetic spinel and alexandrite also exhibit curved striae. The above considerations apply to these stones as well.

Bubbles

Bubbles are common to natural and man made…

Donald Clark, CSM IMG

Donald Clark, CSM founded the International Gem Society in 1998. Donald started in the gem and jewelry industry in 1976. He received his formal gemology training from the Gemological Institute of America (GIA) and the American Society of Gemcutters (ASG). The letters “CSM” after his name stood for Certified Supreme Master Gemcutter, a designation of Wykoff’s ASG which has often been referred to as the doctorate of gem cutting. The American Society of Gemcutters only had 54 people reach this level. Along with dozens of articles for leading trade magazines, Donald authored the book Modern Faceting, the Easy Way.

View All Articles

Previous Lesson

Identifying Inclusions Found in Natural Gems

Go to PREVIOUS Lesson

Next Lesson

Identifying Inclusions Found in Enhanced Gems

Go to NEXT Lesson