The Hidden Beauty of Amber: New Light on an Old Subject
The surprising inner world of inorganic inclusions in amber is explored through the use of polarized light and microscopic techniques.
Inclusions cause chatoyancy in these rare gems.
Describes the phenomenon of pleochroism and its complex effect on the appearance of colored stones.
How contrast patterns can increase perceived brightness and optimize a gemstone's appearance.
A natural cape diamond with unusual features is examined in the New York lab.
HPHT-treated type I diamonds of various colors may exhibit unusually intense fluorescence at the facet edges and junctions.
Millions of carats of turquoise have been enhanced by a proprietary process called the Zachery treatment.
Significant amounts of gem-quality sodalite/hackmanite—some unusually transparent—have been produced.
Four sets of very similar round brilliant diamondswere selected for the different commonly encountered strengths of blue fluorescence they represented.
Examination of samples of faceted "Ocean green" topaz reveals that this material has been irradiated in a nuclear reactor.