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 Philosopher's Stone (Harry Potter, #1)

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

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Lists

Diamonds on Novel Covers

18 books — 4 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

Girl with a Pearl Earring by Tracy Chevalier

A String of Pearls

164 books — 10 voters

The Dreaming Jewels by Theodore Sturgeon

A Little Bit of Crystals by Cassandra Eason

Crystals, Crystalline Structures on the Cover

99 books — 3 voters

By the Shores of Silver Lake by Laura Ingalls Wilder

Jewelry Box

750 books — 102 voters

The Acid Diary by Daniel S. William Fletcher

What would Johnny Depp read?

25 books — 5 voters

Related Genres

Geology
Jewelry
Jewellery
Jewelry Making
Jewels

Minerals
Mineralogy
Lapidary
Jewellery Making
Petrology

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Quotes Tagged “Gemstones”

“ If you pick up a stone on the beach and put it in your pocket, and the very next day something good happens to you, you may start having the belief that that stone is lucky for you. So, you hold on to it as a lucky charm. Now this is completely acceptable self-preservation mechanism, but when fraudsters start selling such stones to the meek and vulnerable, that is not only unacceptable, but downright criminal. ”
― Abhijit Naskar, Aşkanjali: The Sufi Sermon

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“ Let us suppose that this ounce of mud is left in perfect rest, and that its elements gather together, like to like, so that their atoms may get into the closest relations possible. Let the clay begin. Ridding itself of all foreign substance, it gradually becomes a white earth, already very beautiful; and fit, with help of congealing fire, to be made into finest porcelain, and painted on, and be kept in kings’ palaces. But such artificial consistence is not its best. Leave it still quiet to foll Let us suppose that this ounce of mud is left in perfect rest, and that its elements gather together, like to like, so that their atoms may get into the closest relations possible. Let the clay begin. Ridding itself of all foreign substance, it gradually becomes a white earth, already very beautiful; and fit, with help of congealing fire, to be made into finest porcelain, and painted on, and be kept in kings’ palaces. But such artificial consistence is not its best. Leave it still quiet to follow its own instinct of unity, and it becomes not only white, but clear; not only clear, but hard; not only clear and hard, but so set that it can deal with light in a wonderful way, and gather out of it the loveliest blue rays only, refusing the rest. We call it then a sapphire. Such being the consummation of the clay, we give similar permission of quiet to the sand. It also becomes, first, a white earth, then proceeds to grow clear and hard, and at last arranges itself in mysterious, infinitely fine, parallel lines, which have the power of reflecting not merely the blue rays, but the blue, green, purple, and red rays in the greatest beauty in which they can be seen through any hard material whatsoever. We call it then an opal. In next order the soot sets to work; it cannot make itself white at first, but instead of being discouraged, tries harder and harder, and comes out clear at last, and the hardest thing in the world; and for the blackness that it had, obtains in exchange the power of reflecting all the rays of the sun at once in the vividest blaze that any solid thing can shoot. We call it then a diamond. Last of all the water purifies or unites itself, contented enough if it only reach the form of a dew-drop; but if we insist on its proceeding to a more perfect consistence, it crystallizes into the shape of a star. And for the ounce of slime which we had by political economy of competition, we have by political economy of co-operation, a sapphire, an opal, and a diamond, set in the midst of a star of snow. ...more ”
― John Ruskin, Modern Painters: Volume 5. Of Leaf Beauty. Of Cloud Beauty. Of Ideas of Relation

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