ROMANCING THE RUBY

Few words are as packed with meaning as “ruby.” While the word refers primarily to the legendary red gemstone, it is also the preferred adjective for red colors of extraordinary intensity and purity. Its association with wealth and royalty conjures romantic images of kingdoms that once flourished in such historical ruby sources as Ceylon, Siam, Burma and India.

- BY STEVE VOYNICK

Rough ruby crystals recovered from the FURA mine near Montepuez, Mozambique.

FURA Gems

And ruby continues to attract attention today. In June 2023, Sotheby's, the New York City-based, international auction house, auctioned off the largest transparent, gem-quality ruby ever faceted. The stunning, 55.22-carat, cushion-cut Estrela de FURA (Star of FURA) sold for $34.8 million ($630,288 per carat), an all-time record for a colored gem. This spectacular ruby is notable not only for its size and beauty but also for its origin—a newly discovered, major deposit in the East African nation of Mozambique.

RED CORUNDUM

Ruby is a color variety of the mineral corundum or aluminum oxide. As an allochromatic (other-colored) mineral, corundum's colors vary because of the presence of nonessential, color-causing agents called chromophores. Pure corundum is colorless. Red corundum is ruby; all other colors (including colorless) are sapphire. Ruby's diagnostic red color is caused by traces of trivalent chromium which absorb the non-red wavelengths of white light and reflect only the red wavelengths.

Oriental legends describe ruby as the 'spark of life' and 'a drop of blood from the heart of Mother Earth.' Early Burmese cultures believed that rubies 'ripened' with age and that sapphires were 'unripe' rubies, while silky rubies were 'overripe.""

Most ruby occurs in metamorphic rocks. After weathering free from their host rocks, corundum gemstones are sufficiently dense (specific gravity 3.9-4.1) to form secondary alluvial concentrations (placer deposits) that may be of economic importance.