Over the last 10 years, millions of carats of
turquoise have been enhanced by a propri-
etary process called the Zachery treatment.
Tests show that this process effectively
improves a stone’s ability to take a good pol-
ish and may or may not improve a stone’s
color. It also decreases the material’s porosity,
limiting its tendency to absorb discoloring
agents such as skin oils. Examination of
numerous samples known to be treated by
this process revealed that Zachery-treated
turquoise has gemological properties that are
similar to those of untreated natural
turquoise, and that the treatment does not
involve impregnation with a polymer. Most
Zachery-treated turquoise can be identified
only through chemical analysis—most effi-
ciently, by EDXRF spectroscopy—as it con-
tains significantly more potassium than its
untreated counterpart.