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What?
- A precious / semi-precious stone which is earth minerals
- but certain are synthetic or a fossil or just a beautiful rock
- they are cut and polish into desired shapes to make a jewelry
- they have their own beauty, hardness and index of refraction that make them shine
- Rarity is another characteristic that lends value to a gemstone
- precious gemstone - diamond, emerald, sapphire and ruby while other considerate as semi-precious
- classified by the chemical compositions and crystalline structure and crystal habit
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Classification
- Gemstones are classified into different groups, species, and varieties
- 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. Some classified in term of 'water' respect to their clarity, transparency or luster. Example, very clear gems are 'first water' and so on 'second water' and 'third water'
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- No specific grading to crystal value
- but some using 'Four Cs' - Color, Cut, Clarity, and Carat to a diamond
- In crystal gems color also very influencing
- rare gemstone which mean unique one hard to find will add the gem value
Cutting & Polishing
- Some jewel is in their original form as they found
- most of jewel has been cut and and polished to enhanced the beauty and shinny
- Common cutting are cabochons and facets form
Treatments
- Heat - to improve color and clarity for example aquamarine when heat can change color from yellow to green or blue
- Radiation-change color such as quartz,topaz
- Waxing/Oiling-improve clarity and color
- Fracture filling-to make gemstone appear bigger
Synthetic and artificial gemstones
- Some gemstones are manufactured to imitate other gemstones example Moissanite
- However, lab created gemstones are not imitations such as diamond, ruby and sapphire. They can be created but with similar physical characteristics and chemical identity.
