Nowadays designer handbags, wallets, furs, and rings use imitation gems produced in commercial quantities and which are sold wholesale. They give a sophisticated and expensive look to fashion designs. Imitation gems have been perfected so that anyone who intends to purchase precious stones, especially diamonds, should be familiar with the characteristics of the real gem. Unless bought from a reliable jewelry dealer, glass imitations of different densities can easily be mistaken as real.
Diamond imitations are stones that imitate the appearance of a real diamond but do not duplicate its properties. The oldest diamond simulants are glass and grenat-glass doublets. These were later replaced by synthetic spinels and corundums, and diamond-diamond doublets, and the latest manufactured in synthetic rutile, strontium titanate or fabulite, synthetic cubic zirconia (CZ), and in Moissanite.
To avoid purchasing an imitation diamond, test the stone’s properties.
1. Optical Properties. Imitations have a low refraction index that allows light to pass through the stone. Detect an imitation with this simple method.
- Draw a thick black line on a white sheet of paper.
- Place the stone on top of the black line.
If the black line is seen through the stone, the diamond is an imitation. Take note that this simple test is not reliable if the imitation is made from cubic zirconium oxide, fabulite, synthetic rutile, and certain doublets.
2. Hardness. The diamond’s hardness cannot be duplicated; a real diamond cannot be scratched by corundum. Glass imitations are softer and can easily be scratched. Another test is to use an aluminum pencil to draw a line on the stone. An imitation will leave a silvery white line mark.
3. Polish Resistance. Imitation diamonds have soft edges while glass has sharper edges.
4. Color, Luster, Specific Gravity. Glass imitations can have flaws that look natural, but by using a lens, glass will show minute air bubbles that differ in number and shape compared to those in natural minerals. Imitation glass diamonds have a high lead percentage that make them brilliant but soft. A good diamond imitation is made of uncolored strass.
Cheaper stones like quartz, topaz and white sapphire are also used to substitute for diamonds. Only the tests with light, its specific gravity or other properties can help detect imitations. A test for hardness is not reliable.
Reliable jewelers use these tests and can distinguish a real diamond from among a bagful of glass imitations. They also make use of the following tools:
- A reflectometer that uses infrared to compare a stone’s capacity to reflect. Some substances though like ilmenite show the same results as a diamond.
- A conductimeter that tests a stone’s thermal conductibility level. Take caution when testing substances with gold and silver that are very conductible, with small stones and with synthetic corundum, a good thermal conductor.
- An electronic diamond tester that measures the loss of heat using a metallic probe. Diamonds are excellent heat conductors that draw heat faster from probes than simulants. Test the stone in various locations and be cautious of doublets.
Aside from imitation glass diamonds, doublets are also made with part of the stone, a genuine diamond fused with glass. It is harder to detect imitation diamonds if the stones are in a setting. To ensure authenticity, it is suggested that you test and purchase costly stones loose before they are set.
A single test is not sufficient to determine if a diamond is genuine, but knowing its properties will be an advantage to distinguish jewelry that is real or just imitation sold wholesale for designer handbags, wallets, rings, or furs.