From Wikipedia: A gemstone or gem (also called a precious or semi-precious stone, a fine gem, or jewel) is a piece of mineral, which, in cut and polished form, is used to make jewelry or other adornments. However certain rocks, (such as lapis lazuli) and organic materials (such as amber or jet) are not minerals, but are still 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 until the 19th century engraved gems and hardstone carvings such as cups were major luxury art forms; the carvings of Carl Fabergé were the last significant works in this tradition. ~~~ The traditional classification in the West, which goes back to the Ancient Greeks, begins with a distinction between precious and semi-precious stones; 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 8-10 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...
The Smithsonian Handbook of Rocks and Minerals combines 600 vivid full--color photos with descriptions of more than 500 specimens. This authoritative and systematic photographic approach, with words never separated from pictures, marks a new generation of identification guides. Each entry combines a precise description with annotated photographs to highlight the chief characteristics of the rock or mineral and distinguishing features. Color--coded bands provide a clear, at--a--glance facts for quick reference. In addition, each mineral entry features an illustration showing the crystal system to which the mineral belongs. Designed for beginners and experienced collectors alike, the Smithsonian Handbook of Rocks and Minerals explains what rocks or minerals are, how they are classified, and how to start a collection. To help in the initial stages of rock identification, a clear visual key illustrates the differences between igneous, metamorphic and sedimentary rocks, then guides the reader to the correct rock entry. A concise glossary provides instant understanding of technical and scientific terms
Revised and expanded 3E of this very popular guide for Oregon rockhounds and collectors of rock, mineral and fossil specimens. Features over 100 of Oregon's best rock, mineral and fossil collecting sites, including 40 completely new locations. Sites include detailed maps, descriptive text and photos, GPS coordinates, tools required and nearby attractions. With a mineral locator index, glossary, list of mineral clubs and mineral museums, plus a full-color specimen photo insert, this is the indispensable guidebook for either beginning or experienced mineral and fossil hunters.
Perfect for mountain climbers and hikers, this valuable reference covers more rocks and minerals in North America than any other available guide. 794 full-color photographs depict all the important rocks, gems, and minerals -- in many variations of color and crystal form -- and the natural environments in which they occur; written descriptions provide information on field marks, similar rocks and minerals, environment, areas of occurrence, and derivation of names. Includes a guide to mineral collecting and a list of rock-forming minerals
An easy to use field guide that contains everything rock and mineral enthusiasts need to know with more than 1,000 spectacular illustrations—600 in full color!
Practical, concise, and easy to use, Simon & Schuster’s Guide to Rocks and Minerals contains everything that the rock and mineral enthusiast needs to know. This field guide is divided into two large sections—one devoted to minerals and one to rocks, each prefaced by a comprehensive introduction that discusses formation, chemistry, and more. All 377 entries, beautifully illustrated with color photographs and helpful visual symbols, provide descriptions and practical information about appearance, classification, rarity, crystal formation, mode of occurrence, gravity of mineral, rock chemistry, modal classification fields, formational environments, grain sizes of rocks, and much more.
Whether you are a serious collector or an information-seeking amateur, this incomparably beautiful, authoritative guide will prove an invaluable reference.
Unlike the dense and highly technical academic tomes that are text-heavy, poorly organized and intimidating, this colorful and easy-to-use reference guide dedicated to collecting rocks, gems and minerals is ideal for readers who want to expand their understanding without getting lost in a labyrinth of science. Beautifully illustrated with 700 color photographs providing wonderful detail and smartly organized to take the hassle out identification, you will enjoy the simplicity of the guide and the enthusiasm and knowledge of author Patti Polk, one of the top agate collectors in the world and a self-proclaimed "rockhound." You will also enjoy two areas that our competitors don't bother with. First it includes values, and second, it covers an introduction to lapidary, which is the cutting and polishing of rocks and gemstones for jewelry or display.
Heal yourself with power of crystals and gemstones. Hundreds of vivid color photographs make it easy to identify and distinguish between different varieties. Listing for over 140 stones tell you which stones to use for particular illnesses, how to use them most effectively and how stones relate to the chakra system and the signs of the zodiac.
Holly Keller has created vivacious new paintings for this favorite Reading Rainbow title about geology. Readers follow two enthusiastic rock hounds around the globe as they add to their collection. Along the way they will learn how sedimentary, metamorphic, and igneous rocks are formed. From the Egyptian pyramids to Roman roads, from the diamond ring on your finger to the pebbles under your feet'rocks are everywhere!
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