Ruby Vietnam: Information
Since 1983 Ruby Vietnam has become a major ruby producer: Vietnam rubies are striking in their similarity to those from Myanmar, as the geology of the two areas is similar; some experts have found Vietnam rubies to be at least the equal in clarity of Myanmar stones. In a major survey published in the July 2004 issue (vol. 29(3)) of the Journal of Gemmology, Van Long et al. describe the geology of the ruby deposits in northern Vietnam. From 1991 blue, green and yellow (BGY) sapphires have been recovered from alluvial deposits associated with basaltic-type rocks in southern Vietnam and other types of corundum
deposits have been found elsewhere in the country. An earlier paper by Kane et al. in Gems & Gemology 27(3), Fall 1991, also gives a useful account of ruby and sapphire from Vietnam. Pinkish purple sapphires are described; some rubies were found to contain distinct medium dark to dark blue colour zoning.
In northern Vietnam the main ruby-producing sites are in Yen Bai province (the Luc Yen and Yen Bai mining districts) and the Quy Chau deposit in Nghe An province. The southern deposits of BGY sapphires are located at Dark Nong and Binh Thuan in the Dek Lak and Lam Dong provinces respectively. Van Long et al. note a number of other sites.
It is pleasing to know that two exceptional ruby crystals weighing 2.58 and 1.96 kg have been designated as State Treasures and are inalienable. They were found in the placers of the Tan Huong and Truc Lac areas.
Van Long et al. describe the gemmological properties of corundum (ruby and blue sapphire) from the Quy Chau area. Rubies range from purplish red to purplish pink with varying saturations and sapphires are blue. As a contrast the authors describe ruby from the Yen Bai and Luc Yen deposits as showing all tones from red to pink; sapphires range from colourless through pale yellow to grey and blue. Rubies from Luc Yen are usually less saturated than those from Quy Chau. RI and DR are normal for corundum. A notably high SG of 4.08 is recorded for some BGY sapphires from southern Vietnam.
Straight and angular parallel growth features are characteristic of rubies and sapphires from Luc Yen and Quy Chau. Some rubies have been reported to show swirliness long noted for Myanmar ruby. Van Long et al. give a list of solid inclusions for both rubies and sapphires by location of deposit: the commonest mineral inclusions in Luc Yen and Quy Chau rubies are calcite, dolomite, rutile, diaspore and phlogopite. Rutile is found as short needles and also as twinned platy crystals. It may also appear as transparent or opaque orange-brown crystals trapped along growth zones. Zircon has been found in both types of deposit. Fluid inclusions may also contain euhedral negative crystals and flat, broad tubes, some capped by a mineral inclusion. All red and pink samples from Quy Chau and Luc Yen showed red under both types of UV and some blue sapphires from the Khoan Tthong area of Luc Yen also showed red under both types of UV.
Quy Chau produces some beautiful orange sapphires, the colour of papaya, as well as dark blue sapphires and yellow chrysoberyl. At Luc Yen some off-red and blue spinels have been reported and cobalt-blue spinels have also been reported in Vietnam, along with pink and green tourmaline and colourless topaz. The trapiche effect seen in some Colombian emerald and described in the chapter on that species has also been noted in some ruby from Vietnam.