Jewelry designing- Gem stones

Gemstones used in jewelry are given values based on their weight, size, luster, brilliance, transparency, and stones degree of perfection, durability, portability and availability. The relative rarity of stones possessing some or all these qualities has resulted in the classification of gemstones into precious and semi- precious groups.

Precious Stones
There are nine precious stones-:
1.Diamond
2.Ruby
3.Emerald
4.Blue Sapphire
5.Yellow Sapphire
6.Coral
7.Cinnamon
8.Cat’s eye
9.Pearl


Semi precious stones- All other stones believed to be sufficiently attractive when cut and polished to be usable in jewelry are considered semi precious.

Synthetic stones- Today science has devised ways of manufacturing many gemstones by artificially reproducing their crystal structure, and the results are termed synthetic stones.

Color:Color is considered by its hue, tone and saturation.
Hue- pure spectral colors.
Tone- That attribute by which a color is perceived as holding a position on a scale from light to dark.
Saturation- Measurement of the amount of hue in a color
• Color is also considered in terms of a primary and a secondary shade. E.g. bluish green.
• These factors depend essentially on the type of light used .The same stone may behave differently in different light sources.
• The light source should be daylight with a preference for north light (less U.V. radiations).
• The stone should be examined in reflected white light initially. And then in transmitted light.
• Over colored Stone tuned to give misleading idea of transparency. Due to the intensity stone would appear opaque in reflected light


Transparency: The quantity and quality of light transmitted by the stone. Use transmitted light to judge

Transparent(TP)- Transparent stone usually are cut with facets to allow maximal dispersion of light within the stone. The quantity and quality of light transmitted by the stone. Transmits light readily; can read through easily, even if colored. E.g. diamond, ruby emerald etc.

Opaque(OP)- Opaque stones are generally cut in cabochon. Transmits no light .E.g. Pyrite, Hematite, Laces Lazuli.

Translucent(TI)- Translucent stones may be cut either way. Transmits a very small amount of light. Primarily around the edges. E.g. star garnet.

Semi-Transparent(S-TP)- Transmits light somewhat less readily; can read through but with slight distortion (Somewhat hazy). E.g. Amber and moonstone.