Gemstones

This easy-to-use guide to gemstones contains more than 130 entries (145 pages) of full-colour photographs with descriptions.

Divided into five sections, including a section on mineral gemstones and one on organic gemstones, this book guides you through the subject of gemmology and introduces you to the main gemstones used by jewellers, healers and collected by gemstone enthusiasts. There is an entry for each gemstone, plus an extra introductory page for those with more than one gemstone in the ‘family’ – for example, beryl, which includes emerald and aquamarine.

For each gemstone, there is a colour photograph to help you recognise it. Photographs of well-cut gemstones show what they look like before they are set in jewellery. There are also photographs of gemstones set in spectacular pieces, designed to show them to their best advantage. The jewellery includes historical, famous and modern pieces. Gemstones that are best polished, for example as slices for inlay or mosaic work, domed shapes (cabochons), cameos, intaglios or carvings, are illustrated with appropriate photographs.

To help you find what you are looking for, each gemstone has information along the side of the page, which includes:

• a line diagram of the typical crystal shape

• the name of the gemstone

• the name of the gemstone ‘family’

• hardness

• the page number.

The text on each page tells you about each gemstone. You may want to know why the gemstone has the name that it has;for example, it may be because of its colour, where it was found or perhaps because of its chemistry.

Maybe you are interested in knowing a little of the history of the gemstone, who first found it, whether ancient civilisations held it in awe and how they used it as a decorative gemstone or perhaps even a weapon.

You might like to know about the myths and legends and the beliefs held by healers that are associated with some of the gemstones. Each gemstone has its own story to tell. This book is for you to find out some of those stories.

To help you use the book as a reference source, information is clearly shown in boxes and tables individually alongside each gemstone and at the back of the book. Turn to page 174 to find out more about what these headings mean:

• name

• chemical formula

• crystal system

• hardness

• Specific Gravity (SG)

• Refractive Index (RI)

• Birefringence (DR)

• lustre.

If you have ever walked along a beach and picked up a pebble, or seen something shining or twinkling on the ground and stopped to have a look, you will know the feeling of seeing that special something that catches your eye, that you want to have a better look at, that you may want to keep.

The outcome of this fascination is that gemstones have been coveted through the ages as something special, something even worth dying for. Surrounded by myths and legends, gemstones have attained a particular significance that has lasted for centuries;from prehistoric beads and ornaments to the present-day jewels of the royal families, engagement and wedding rings worn to celebrate marriage, and the ‘bling’ worn by both men and women.

But what makes a gemstone? Gemstones have always been associated with adornment, wealth and fame. Nowadays almost any material can be used to fashion jewellery for adornment for practically any part of the body, or to adorn fashion accessories such as shoes, handbags and hats. Artists and sculptors may also use gemstones in their creations. Plastics, glass, wood and clay are used in what is termed ‘costume jewellery’, some are faceted and called ‘gems’, but are they gemstones?

A gemstone is defined, by jewellers and gemmologists (those who study gemstones scientifically), as having three attributes:

• beauty

• durability, and

• rarity.

Beauty is essential for all gemstones, as the prime objective is to have an attractive product. But, as they say: ‘Beauty is in the eye of the beholder.’ A faceted gemstone may be preferred by some, while others find more beauty in an uncut rough crystal still in its ‘natural state’.

Durability, the strength and hardness of a gemstone, determines how well it will last without becoming scratched, chipped or worn. For a gemstone to keep its sparkle, not just for months or years, but for generations, it should be tough and have a hardness of more than 7 on the Mohs’ scale (which measures the hardness of each gemstone on a scale of 1 to 10 –