How to Identify Ruby Simulants and Synthetics

Key Takeaways for Identifying Ruby Simulants and Synthetics

In this article, you’ll learn the following:

• How to distinguish rubies from most ruby simulants with basic observations and tests
• How the optical and physical properties of the most common ruby simulants differ from those of ruby
• Why flame-fusion rubies are the only synthetic rubies most gemologists will likely ever examine
• How to distinguish flame-fusion rubies from natural rubies with just a microscope and a little practice

A Brief Review of Ruby’s Chemical and Crystallographic Properties

• Ruby belongs to the corundum mineral species. This species includes all varieties of sapphire, too.
• By definition, red corundum is ruby. Corundum with any other color, including colorless, is considered sapphire.
• All corundums form in the hexagonal (trigonal) crystal system and grow naturally as six-sided crystals. Rubies tend to form as flat, tablet-like crystals. Sapphires tend to form as double pyramid-shaped crystals.
• Pure corundum is a colorless aluminum oxide with the chemical formula Al₂O₃. When different metal impurities are captured during the growth process, the crystals will have different colors.
• Ruby’s red color comes from minor traces of