|
|
| |
Pearl
Name and Facts:
The derivation of the name is uncertain but maybe from a type of shell(Latin-Perna) or from its spherical shape (Latin-Sphaerula). Pearl are produced by molluscs, rarely by snails. They consists of mother-of-pearl, which is mainly calcium carbonite (in the form of aragonite), and an organic horn substance(conchiolin) which are formed concentrically around microcrystals. They have hardness in Mohs' scale around 3-4. They specific gravity is 2.60-2.78 gr/cm3. The largest pearl ever found weighs 450 cts or 90 gr. It is in South Kensington Geological Museum in London.
Cultured Pearls
The increased demand for pearls has led to their cultivation . Such cultured pearls are not imitation, but a natural product which has been produced with man's help. Today cultured pearls amount to over 90% of the total pearl trade. A bid (mostly rounded mother of pearl bid) is inserted into the mollusc.
Pearl Grading
Pearls are graded based on their nacre thickness, luster, surface texture, color, size, shape and matching. A combination of these characteristics decides the overall quality and value of pearls.
|
Grade
|
Nacre
|
Luster
|
Shape
|
Blemishes
|
Matching
|
|
A to A+ Quality
|
Thin
|
Medium
|
Round
|
Medium
|
Medium
|
|
AA to AA+ Quality
|
Medium
to Thick
|
Medium
to High
|
Round
|
Light
|
Very
Good
|
|
AAA
Quality
|
Very
Thick to Extremely Thick
|
Very
High to Extremely High
|
Round
|
Flawless
|
Excellent
|
How to Take Care of Pearls
Pearls have been regarded as one of the most valuable gem materials. They have been used for adornment for 6000 years.
There is little difference between the cultured and natural pearls.
How to Take Care of Pearls
|
|  |
|
|
|
|
|
|
|