Costantini Rediscovers Neglected Gem

If you’ve ever picked up a standard gemological text on the subject of opals, you probably learned that they were discovered in Czechoslovakia. That was the sum total of information available on Czech opal—until now.

Dr. Luigi Costantini, geologist and gemologist with the International Gemological Institute Italy, has written The Slovak Opal: A Rediscovery of the “Queen of the Gems,” for Gem Lovers and Tourists.

The story begins in Eastern Slovakia, which, until the end of the 19th century, was the world’s sole source of opal. It describes the area, its commerce, mine localities, the people who dug for precious opal, the landscapes, and individual mining sites. Costantini is a mineralogist, so there’s plenty of gemological information, as well.

Other sections include the classification of Slovak opal; quality grading and cutting; and references in literature, myths, and legends. The book also has an excellent glossary and index.

It’s available for $59.95 at all IGI lab locations and at