Impregnated and Dyed Turquoise
Natural turquoise has been subjected to dyeing and three types of impregnation.
The Identification of Zachery-Treated Turquoise | Gems & Gemology
Millions of carats of turquoise have been enhanced by a proprietary process called the Zachery treatment.
Abstracts; Winter 1991
This article, from the Winter 1991 issue of Gems & Gemology, is a compilation of abstracts of important gemology-related articles published outside of Gems & Gemology.