Gemstones

A gemstone (also called a gem, fine gem, jewel, precious stone or semi-precious stone) is a piece of mineral crystal which, in cut and polished form, is used to make jewelry or other adornments. However, certain rocks (such as lapis lazuli) or organic materials that are not minerals (such as amber or jet) are also used for jewelry and are therefore often considered to be gemstones as well. Most gemstones are hard, but some soft minerals are used in jewelry because of their luster or other physical properties that have aesthetic value. Rarity is another characteristic that lends value to a gems A gemstone (also called a gem, fine gem, jewel, precious stone or semi-precious stone) is a piece of mineral crystal which, in cut and polished form, is used to make jewelry or other adornments. However, certain rocks (such as lapis lazuli) or organic materials that are not minerals (such as amber or jet) are also used for jewelry and are therefore often considered to be gemstones as well. Most gemstones are hard, but some soft minerals are used in jewelry because of their luster or other physical properties that have aesthetic value. Rarity is another characteristic that lends value to a gemstone. Apart from jewelry, from earliest antiquity engraved gems and hardstone carvings, such as cups, were major luxury art forms. A gem maker is called a lapidary or gemcutter; a diamond worker is a diamantaire.

The traditional classification in the West, which goes back to the ancient Greeks, begins with a distinction between precious and semi-precious; similar distinctions are made in other cultures. In modern usage the precious stones are diamond, ruby, sapphire, and emerald, with all other gemstones being semi-precious. This distinction reflects the rarity of the respective stones in ancient times, as well as their quality: all are translucent with fine color in their purest forms, except for the colorless diamond, and very hard, with hardnesses of 8 to 10 on the Mohs scale. Other stones are classified by their color, translucency and hardness. The traditional distinction does not necessarily reflect modern values, for example, while garnets are relatively inexpensive, a green garnet called tsavorite can be far more valuable than a mid-quality emerald. Another unscientific term for semi-precious gemstones used in art history and archaeology is hardstone. Use of the terms 'precious' and 'semi-precious' in a commercial context is, arguably, misleading in that it deceptively implies certain stones are intrinsically more valuable than others, which is not necessarily the case.

In modern times gemstones are identified by gemologists, who describe gems and their characteristics using technical terminology specific to the field of gemology. The first characteristic a gemologist uses to identify a gemstone is its chemical composition. For example, diamonds are made of carbon (C) and rubies of aluminium oxide (Al2O3). Next, many gems are crystals which are classified by their crystal system such as cubic or trigonal or monoclinic. Another term used is habit, the form the gem is usually found in. For example, diamonds, which have a cubic crystal system, are often found as octahedrons.

Gemstones are classified into different groups, species, and varieties. For example, ruby is the red variety of the species corundum, while any other color of corundum is considered sapphire. Other examples are the Emerald (green), aquamarine (blue), red beryl (red), goshenite (colorless), heliodor (yellow), and morganite (pink), which are all varieties of the mineral species beryl.

Gems are characterized in terms of refractive index, dispersion, specific gravity, hardness, cleavage, fracture, and luster. They may exhibit pleochroism or double refraction. They may have luminescence and a distinctive absorption spectrum. Material or flaws within a stone may be present as inclusions.

Gemstones may also be classified in terms of their "water". This is a recognized grading of the gem's luster, transparency, or "brilliance". Very transparent gems are considered "first water", while "second" or "third water" gems are those of a lesser transparency. ...more

Gemstones Books

A Court of Mist and Fury (A Court of Thorns and Roses, #2)

Harry Potter and the Deathly Hallows (Harry Potter, #7)

More gemstones books...

Lists

Girl with a Pearl Earring by Tracy Chevalier

A String of Pearls

164 books — 10 voters

Jewellery - Diamonds, Gold and Stones on Covers

370 books — 141 voters

The Story of Ruby Bridges by Robert Coles

The Hound of the Baskervilles by Arthur Conan Doyle

Characters with Jewel Names

262 books — 32 voters

Harry Potter and the Sorcerer's Stone by J.K. Rowling

Sylvester and the Magic Pebble by William Steig

Magic Stones

127 books — 14 voters

Hey Hue-Man Where Is Our Food by Toni Crowe

To The Bright Edge of the World by Eowyn Ivey

Who Educates Parents? by Žilvinas Svigaris

The Travelling Cat Chronicles by Hiro Arikawa

Books that are under-appreciated gems.

388 books — 86 voters

All I Wanted Was Sushi But I Got Abducted By Aliens Instead by Petra Palerno

"Opal"

41 books — 8 voters

Related Genres

Geology
Jewelry
Jewellery
Jewelry Making
Jewels

Minerals
Mineralogy
Lapidary
Jewellery Making
Petrology

Featured News & Interviews

Readers’ Hit New Books of the Year (So Far)

Read »

Quotes Tagged “Gemstones”

“ Your mom is my sunset, and you are my dawn. ”
― Larissa Ione, Eternal Rider

41 likes

“ Up then, fair phoenix bride, frustrate the sun; Thyself from thine affection Takest warmth enough, and from thine eye All lesser birds will take their jollity. Up, up, fair bride, and call Thy stars from out their several boxes, take Thy rubies, pearls, and diamonds forth, and make Thyself a constellation of them all; And by their blazing signify That a great princess falls, but doth not die. Be thou a new star, that to us portends Ends of much wonder; and be thou those ends. ”
― John Donne, The Complete English Poems

71 likes

More quotes...