Step 3: Practical Gemology
While preparing this lesson in gemstone examination, I was in the process of professionally identifying the following stones. Rather than create fictional examples, I decided to use the photos and descriptions of these actual gems and real-life cases to illustrate the procedures and problems you’ll encounter as a fledgling gemologist.
Gemstone Examination: Example 1
This stone looks like a tourmaline. I made that initial assessment based partly on its shape – tourmaline crystals are elongated, so rectangular gems are common – and partly on its color – green, but slightly grayish. It’s certainly not an emerald or other chromium-colored gem.
The end facets are black. No light was passing through them. This is called a “closed C axis” and is common to tourmaline, but little else. For our purposes, we’ll simply note that the stone has strong pleochroism.