Both metals and stones are tested in order to evaluate your jewelry. The metal testing is a non-destructive process whereby we make a small scratch of the metal to be analyzed on a testing stone. The residue is then treated with various acids to determine the karatage. The testing is done for karat gold, platinum and silver.
Stones are tested in a different way. The most often-used tool is the microscope. By virtue of the inclusions, a preliminary identification can be made. For confirmation, we use a refractometer, which measures the speed of light inside the stone. Creating a contact between the stone and the refractometer by use of a special liquid does this. This liquid allows for a numerical reading, which is then applied to a known chart of indices. This test is also non-destructive.
A polariscope can also be used for identifying some different types of stones. This instrument is used for identifying singly and doubly refractive stones as well as some types of synthetics.
Ultraviolet light can be useful as well as a series of filters for coloured stones.
Yantz Bradbury Associates
P.O. Box 10123
Rockville, Maryland 20850
Office: (301) 335-6687
Serving MD, VA and DC Metro Area