Emerald – The Most Valuable Member of the Beryl Family

At one time all green gemstones were refered to as emeralds.  When we were able to determine that not all green stones were emeralds, we also discovered that some of the Egyptian Queen Cleopatra’s Emeralds were infact another less expensive green gemstone called Peridot.

Hooker Emerald Brooch Smithsonian

Photo by J McKercher

This is the 75ct Hooker Emerald Brooch.  This brooch is found at the Gem and Mineral Collection of the Smithsonian’s National Museum of Natural History.

After determining that not all green stones were emerald gemmologists were then able to determine that emerald has the same chemical composition as Aquamarine (light blue or light green), Heliodor (yellow/golden), Goshenite (colourless), Green Beryl lLight green), Bixbite (red) and Maxixe (dark blue that fades in daylight).  These are all varieties of beryl.

They are all Beryllium Aluminum Sillicate [Be3Al2(SiO3)6].  It is the trace impurities of chemicals that cause the different colours.  Emeralds have trace elements of chromium, aquamarine is coloured by iron.  If you have a beryl that is a light green, but not the deep green tone of emerald, then it is called green beryl and it may be coloured mainly by iron.  The GIA now identifies beryl coloured green by vanadium as emerald, Gem-A does not.

Morganite at the Smithsonian

Photo by J McKercher

Emeralds can be found in Afghanistan, Brazil, Colombia, India, Packistan, South Africa, former USSR, Zambia, Zimbabwe and the USA.  The best ones come from Colombia.

Emeralds at the Smithsonian

Photo by J McKercher

Most emeralds on the market today are treated to increase their durability and to enhance their colour.  An emerald at a very good price may actually be a synthetic, this means it has the same chemical composition and crystal structure as the natural emerald, but it was grown in a laboratory.   Don’t go by the rule that if it has inclusions then it is natural, many synthetic methods leave tell-tale inclusions in the synthetic stone.  A good gemmologist can determine if it was created by the hydrothermal method or the flux synthetic method.

Emeralds at the Smithsonian

Photo by J McKercher

Be very careful when purchasing an emerald!  Maybe it is green beryl, peridot, an imitation emerald or a synthetic emerald.  If you can afford a natural emerald you should find out what treatments has it undergone.  Time to make friends with a gemmologist.

Galdiators?

Gladiator fight

Flickr photo by H Splinter

Pliny the Elder (AD23-AD79) reported in his Historia Naturalis that, in olden days, beryls were used as eye glasses.  It is said that the Emporer Nero watched galiator fights through an emerald.  I guess he could afford emeralds without many inclusions!

Your Input (Join our poll or scroll down and leave a comment) – Emerald is winning the poll!

I plan to introduce different gemstones alphabetically.  I will start with “A” (Ammolite) and see where it leads me.  Leave a comment and let me know if you have a favourite gemstone that starts with the letter “F”.  Take the poll!  Can you name a reference to a gemstone in a song, movie or book?

Advertisements

About Jen McKercher

Jennifer McKercher teaches gemmology at the Canadian Gemmological Association. A passion for gemstones drives Jen to learn as much as she can about the wonders of gemstones and how they enhance our lives.

Posted on July 14, 2011, in Individual Gemstones and tagged , , , , , , , , , , , , , , , , , , , . Bookmark the permalink. Leave a comment.

Leave your thoughts!

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: