While single stones can be tested for authenticity, colour and clarity treatments and—for ruby, sapphire, emerald, alexandrite, Paraiba tourmaline and spinel—for country of origin, melee-sized gemstones can only be economically tested for authenticity plus colour and clarity treatments; the determination of country of origin in an economic way is only possible exceptionally and with limitations. Compared to single stones, the most important difference in the testing procedures needed for melee-sized gemstones is efficiency; testing must be rapid and accurate, in order to make commercial sense.

Author

• Dr. Thomas Hainschwang, GGTL Laboratories Liechtenstein. ResearchGate, Linkedin.

© International Colored Gemstone Association. This article was published in "InColor". (2019), Issue 42, Fall, pp 58.