Cobalt-Colored Composite Sapphires Now Entering the Market
Photomicrograph by Christopher P. Smith magnified 68x.
A couple of samples of cobalt-colored composite sapphires—a new type of treatment— were sent to AGL for testing.
Populating the interior of these Composite Sapphires are numerous contraction bubbles and irregular black, reflective particles. Also note the “pool” of blue colored glass surrounding the largest contraction bubble. Other inclusions related to the host corundum were also evident but are not seen in this image. These included small crystals of foreign minerals, with fine rutile needles and pinpoint particles, indicating that only relatively low-temperature heat is invalid with this treatment process.
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