Guide to Gems: Illustrated Guide to the Identification, Properties and Use of Gemstones (Firefly Pocket)

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Gemstones is filled with all you need to know about these fascinating minerals - cut and uncut stones, organic gemstones, and precious metals. Inside you'll find:

Most gemstones can be safely dipped in silver dip or gold dip, but not pearls and great care should be taken when cleaning jewellery set with opals, for further tips see our Caring for your Jewellery guide. The Four Precious Gemstones Did you know that glittering refers to the luster of the gold or the quality of the light that is reflected from its surface? The gleaming sheen of polished gold contrasts sharply with the dull luster of raw gold, which barely reflects when compared to its brilliant metallic luster. Fossilized tree sap from ancient rainforests. Amber is often found along the beaches of the southeast of England where it washes up after a very long journey. Resinous luster is comparable to the appearance of resin or smooth plastic. Amber is one of the most well-known gems with a resinous luster, which makes sense given that it is classified as a plant resin. Others include sphalerite, sphene and vesuvianite.

What Are Gemstone Facets?

Gemstones and crystals are used for jewelry, industry, lasers and precision technology. Firefly Guide to Gems is a practical, compact guide to the identification and use of precious and semi-precious stones, novelty stones, agates and crystals.

The most famous gem of them all? Almost certainly, and all thanks to its remarkable fire, effortless brilliance and clarity to die for. Essential. A gemstone’s polish luster, or how it appears after polishing, can be very different from its base luster. For instance, polishing can turn jet, which has a dull or waxy base luster, into vitreous. Any gem other than a translucent diamond. If you want dazzling jewelry with a refreshing color, see our Sapphire Buying Guide. What is the best gem cut?

Optical Phenomena

Because polished gems with high lusters usually have high refractive indices, and polished gems with low lusters typically, but not always, have lower refractive indices, luster can be a useful observational feature to identify. Adamantine Silky. Greasy? Gemologists use various evocative terms to describe gemstone luster. This refers to the appearance of a gem’s surface when it reflects light.