Jewelry Designing - What is a Gem Stone?

• To identify a gemstone there are a number of very accurate tests which a jeweler-gemologist can make use of.
• Each gem species has characteristic physical and optical properties which are constant
Within narrow limits and to a certain extent can be objectively determined.
• However, a basic fact which must never be forgotten is the importance of a visual identification.
• An unknown stone can be classified by correctly perceiving its color, cut transparency,
Luster, dispersion, heft, as well as any phenomenal properties etc.
• The type of lighting in which each of the properties is observed is also important.

What is a gem stone?
Beauty, Rarity & Durability: B, R, D, is one of the basic concepts by which a
Material can be defined as a gemstone.

Beauty: This is a subjective property and is defined by the four C’s’, Color, Clarity,
Cut and Carat size. The presence of a phenomenon also enhances the beauty of a gemstone.
- Color: In colorless stones, the lesser the color the better the quality. In colored stones, the darker and purer the shade of color, the better the quality.

- Clarity: This is defined by the presence or absence of inclusions within a stone which indicates the transparency. This can be more objectively judged by.
- Number of inclusions
- Size of inclusions
- Position of inclusions
- Color of inclusions

- Cut: A stone which has been cut and polished keeping in mind the accurate angles and proportions of cutting, which bring out the full life, fire and brilliance of a gemstone. The beauty of a particular cut can be observed by examining the type of cut. And the summery and polish on the crown, pavilion and girdle portions of the stone.

- Carat size: This relates primarily to the weight of a stone.

1 carat = 100 cents / points =200mg.
The larger the size, with good color and clarity, the higher the value.
Weight of the gems, i.e. larger the stone with good color and clarity, higher the value.

Rarity : The is an important aspect and may either be due to natural resources or due to man made situations.
- If a gemstone is available in large quantities, it will not be much in demand.
- If a gemstone has all the four C’s’ and a phenomenon, it would be rare.
- Political and economic conditions in country can control the supply to demand ratio of rough and cut stones.
- If a stone has a limited geological and geographical occurrence i.e. from a single source e.g. red beryl from Utah (USA)

- Durability: A gemstone must be durable enough to withstand dally wear and tear. This includes the qualities of hardness, cleavage, brutality toughness resistance to heat pressure or chemicals.

- A softer stone will get scratched more easily.

- A stone with a number of internal cracks will be less durable.

- A stone with easy cleavage e.g. diamond topaz etc. may split into two if it suffers a hard knock.

- Perspiration, perfumes lime juice etc. may damage less resistant gem materials such as pearls.