Reflections on origin determination

In our webshop we state, whenever possible, the geographic origin of gemstones, sometimes even down to the very mine.

Why is determination of origin important?

The value of gemstones is determined by the famous 4Cs, colour, carat, clarity and cut.

However, in many gemstones origin also has a certain influence on price.
Mostly this is because of the mine´s history and it´s reputation of supplying gems of truly excellent quality.

Two of the best known examples are Kashmir sapphire and Burma ruby.

The only two mines for Kashmir sapphires were worked for a mere six (old mine) and about thirty years (until 1927) before they were depleted.  However, the gems mined in this short period were of outstanding quality. Kashmir sapphires became an instant legend and until today set the standards for all blue sapphires.

With Burma ruby the situation is different because the mines are still operative. Mogok has been the source of fines rubies for about 800 years! Over time more ruby locations were discovered. Some, like Longido in Kenya, supply rather poor qualities only, or, like Sri Lanka, are known for moderate qualities, at best. The finest specimens coming from some sources, however, like Jegdalek in Afghanistan, Luc Yen in Vietnam or Montepuez in Moçambique, match fine Burma rubies.

Nevertheless Burma rubies fetch significantly higher prices than rubies of the same quality from other sources. This is because we do not just buy a ruby, we also buy it´s history, it´s legend and lore. After all Mogok was the only source for many centuries and supplied all the fine rubies that adorned the hands, necks and crowned heads of the rich, the famous and the royalty of the world.

How is geographic origin determined?

By and large origin is determined by studying the gem´s inclusions and, increasingly, by analyzing trace elements typical of the location.

Microscopic study of gemstone inclusions started at the beginning of the 20th century, when synthetic gems entered the market in large numbers, which made it necessary to distinguish them from their natural counterparts.

The foundation stone of miscroscopic gem identification and origin determination was laid by the world´s most famous gemmologist, Eduard Josef Gübelin of Switzerland, whose illustrated book Internal World of Gemstones, published 1974, and the two-volume monumental work Photoatlas of Inclusions in Gemstones, published in 1986 and 2008, in co-operation with American gemmologist John I. Koivula, revolucionized the study of gemstone inclusions. These books immediately became standard reference literature and are indispensible for every gemmological laboratory the world over.

The second pillar of origin determination is formed by various methods of spectroscopy and spectrometry, such as UV-spectroscopy. infrared spectroscopy, Raman spectroscopy and laser ablation mass spectrometry. With these techniques minute quantities of trace elements like gallium, vanadium, magnesium, iron, gadolinium etc, which often are typical of certain locations, can be detected. Thus Burma rubies in general show a higher content of vanadium than comparable rubies from Vietnam, Afghanistan or Tadzhikistan.

Now, data from various sources often overlap. There are, for instance, Burma rubies with low vanadium content and unusually vanadium-rich rubies from Vietnam. However, element analysis in combination with microscopic studies and ever growing data banks provide modern gemmologists with very powerful tools, indeed.