Hydrothermal Ruby

Rubies grown by the expensive and time consuming hydrothermal process may take over a year to reach suitable sizes.  Unlike the cheap flame-fusion synthetic ruby, hydrothermal ruby grows as natural looking crystals with natural like growth features such as angular banding and crystalline inclusions.  With such genuine looking features and colours that are said to match the finest Burmese and Thai rubies, it is little wonder that hydrothermal ruby is considered to be the best alternative to natural ruby.  Hydrothermal ruby mimics natural ruby in so many ways that only well trained gemmologists can differentiate them from natural material.
Mohs’ Hardness: 9
Specific Gravity: 3.80-4.05
Refractive Index: 1.760-.1778
Birefringence: 0.008-0.009
Optic Sign & Character: Uniaxial Negative
ICA Code: S
Treatments: None
Incidence: N/A
Purpose: N/A
Durability: Very good
Detection: Microscopy
Special Care: None
Synthetics: Flame-fusion
Possible Imitations: Glass, doublets