Emerald - the symbol of rebirth and bringer of good fortune and youth - is the birthstone for those born in May.
A variety of green beryl, the name emerald is derived from the Greek word smaragdus (green in Greek). The green colour of emerald is caused by traces of chromium, but vanadium may also be present in some stones.
Emeralds can be found in Colombia. Brazil, India, Pakistan, Siberia, South Africa, Zambia and Zimbabwe.
The inclusions contained in almost all natural emeralds are very useful in distinguishing natural emeralds from synthetic emeralds and other green stones. Some inclusions are common for particular localities.
Typical Inclusion and Features
Three-phase inclusions (liquid-filled cavity containing a crystal and a gas bubble)
Two-phase inclusions (liquid-filled cavity containign a gas bubble)
Tremolite (usually fibrous or neddle-like crystals)
Needle-like crystals of actinolite
Mica flakes, pyrite and calcite, and also colour zoning
Combining the typical inclusions found with an assessment of refractive index and specific gravity can give an indication of the country of origin. ■
Calling all diamond aficionados! Two of the largest, purest white diamonds ever to come to auction will be presented at Sotheby’s Geneva on May 15. Here, we find out more about these flawless D Colour, Type IIa diamonds that weigh over 50 carats each.
We often hear the phrase “the sap is rising” in reference to the early days of spring, which makes the sunny glow of amber a most appropriate gem for those born under the star sign of Taurus (20 April – 21 May). Here, Gem-A senior tutor, Rona Bierrum FGA DGA, shares some of the myths and legends that surround amber.
With some of the industry's biggest players experimenting with blockchain technology, Gem-A tutor Beth West FGA DGA, discusses the turbulent history of diamonds and how this emerging digital ledger can help to redeem their reputation among customers.
Guy Lalous ACAM EG is on-hand to summarise some of the more in-depth articles from Gem-A's The Journal of Gemmology. Here, he delves into a feature on Mexican amber and the use of FTIR spectroscopy to determine provenance from the Winter 2017 issue.