How Are Diamonds Made? Natural vs Lab-Created Explained
Two Paths, One Diamond Not all diamonds come from the same place — but they all start the same way. Pure carbon, crystalized under immense pressure and heat. Whether it…
Executive Director, AGS Laboratories and Gemological Sciences
Last 5 articles of this author
The Effects of Indexed Upper Half Facets
by Peter Yantzer, CG
American Gem Society Laboratories
Gemstone cutters can tilt or 'index' the upper half ( or upper girdle ) facets. This indexing produces different amounts of weight retention from a given piece of rough and produces different optical performance effects. Indexing can also affect cr...
The Effects of Indexed Upper Half Facets
by Peter Yantzer, CG American Gem Society Laboratories Gemstone cutters can tilt or 'index' the upper half ( or upper girdle ) facets. This indexing produces different amounts of weight retention from a given piece of rough and produces different optical performance effects. Indexing can also affect cr...
