Emerald; The Birthstone for May
The mineral world celebrates the month of May with a special green gemstone; Emerald. Emerald is the greenish variety of a family of minerals known as beryl which also includes aquamarine (which is the blue variety), heliodor (golden-yellow variety), morganite (orange-pink variety).
Beryl, which is beryllium aluminum silicate, is a rare mineral with a chemical composition of Be3Al2(SiO3)6. In its pure form, beryl is white and is called goshenite. Emerald gets its light to deep green colour from presence of chromium and/or vanadium that replace some of the aluminium in the mineral’s structure. The May birthstone is considered to be a symbol of rebirth and love and has its name derived from the French word “esmeraude”, whose Greek root “smaragdos” means ‘green gemstone’.
Deep grass green emeralds are more desirable than the lighter green shades or the ones with bluish or yellowish tone (the latter indicates trace amounts of iron). Very pale-coloured stones are called green beryl, and are usually treated by heat to turn their colour blue and transform them into aquamarine. Emerald is rare because beryllium which is one of its key elements occurs sparsely in the earth’s crust and the conditions in which beryllium occurs significantly differ from conditions that favour chromium and vanadium (which are the sources of emerald’s green colour).
Emerald forms as a six-sided symmetrical crystal with hardness ranging between 7.5 and 8 on the Mohs scale, a factor that makes them suitable for jewellery. However, most emeralds contain many inclusions or surface-reaching cracks and fissures which weaken them, make them brittle and subject to breakage. To correct this, polishers/cutters usually immerse them in oil to reduce the visibility of inclusions and to improve their clarity.
Like other stones, its price tagged to size and quality (colour and presence of fissures or inclusions). Due to its fragility nature, emerald is best worn on special occasions rather than daily and is best suited for earing and pendants. They are mined all over the world with Colombia leading in the production of large and quality emeralds. Other countries include Brazil, Zambia, Madagascar, Afghanistan, Pakistan, Russia, Australia, India, United States, Pakistan, Norway, among others.
Read more interesting articles about minerals and other birthstones on this link: https://www.mininghubafrica.com/category/minerals/