Diamond Testers: How reliable are they?
You need several diamond testers, electronic instruments (cost!) and you must know how to use them.
Conventional testers will differentiate on thermal conductivity and on digital reflectivity but…
still nothing is foolproof for a non professional! Buying a diamond mostly you do not carry diamond testers.
Conventional diamond testers will differentiate between diamonds and most simulants based on thermal conductivity. This is the ability of a substance to conduct heat. Diamonds conduct heat very well, while most simulants simply do not.
Note: moissanite is also a good conductor of heat.
A stone that tests as a diamond on a conventional diamond tester, can also be found to be moissanite.
A conventional diamond tester will have a metal tip that becomes hot and measures the amount of heat loss from the tip when applied to another substance.
When the same tip is applied to a diamond, the diamond takes the heat from the tip and then the tester will show as a diamond.
Some simulants, like the white sapphire, can also conduct heat but not quite as well as a diamond.
A diamond tester needs to be able to distinguish these lesser conductors from real diamonds. Most diamond testers will not register diamonds for such items.
A problem when testing diamonds can occur if the tip of the diamond tester accidentally touches a metal prong.
If the item is a good conductor of both heat and electricity, then metal was touched. (Note: Moissanite will also conduct electricity, but not nearly as well as a diamond and the metal indicator should not work if the stone is moissanite.)
A method of distinguishing diamonds from moissanite must be used. There are several different methods available now, so it is necessary to test a stone in several places using a moissanite tester.
A conventional diamond tester must always be used first. This will show without any doubt? that the stone is either a simulant or
diamond/moissanite. Once a stone can be proven to be a regular simulant, there is no reason to further test it on a moissanite tester.
An electrical conductivity tester, such as the MT2 Moissanite Terminator, will indicate moissanite and would ideally be used after a thermal diamond tester has eliminated other simulants.
How to test rough, raw uncut diamonds: Fake rough diamonds are generally coated with diamond powder on glass.
A diamond tester will show you that it is rough diamond!
How to test fake rough, raw uncut from real diamonds: Cut or polish a part of the surface of the rough to eliminate the coated surface.
Than test with the diamond tester on the cut or polished part of the diamond.
Affordable Diamond / Gold Testers, electronic instruments, for the gemologist, jeweler, appraiser, and lapidaries: http://www.gemworld.com/DiamondTesters.asp - http://www.swissaxe.be/products/testers/gold_tester.html
Detect, tests on HPHT and Synthetic diamonds:
D-Screen, a practical analysis. It identifies natural diamonds from synthetics or / and color improved by means of HPHT -
developed by HRD - Diamond High Council in Antwerp World Diamond Center.
HPHT treatment must be indicated on the certificate and laser inscribed on the girdle of the diamond (from reliable labs)
Test diamonds by Specific Gravity, Density, Hardness, Weight + Refraction of Precious stones, Minerals