This paper introduces the description and identification of diamonds, colored jewelry, pearls and jade.
Diamond
Colored jewelry
Pearl
jade
Diamond
Diamonds are described and graded according to different standards such as National Standard, GIA, CIBJO, HRD, IDC, etc. The following should normally be included:
(1) Origin: indicates whether the diamond is natural or synthetic, whether it has been optimized and treated.
(2) Carat weight: Specify the actual weight of the diamond, and indicate whether it is directly weighed or measured, using the formula to estimate the weight.
(3) Color grade: According to the relevant standards, determine the diamond color grade.
(4) Clarity grade: diamond clarity grade determined according to relevant standards.
(5) Cutting grade: according to the relevant standards, the diamond cutting grade is determined.
Colored gemstone
Commonly used colored gemstone grading standards (such as GIA. GemDialogue, etc.) are used to describe and grade colored gemstones. The following should normally be included:
(1) The variety of gems: what kind of gems the colored gems are.
(2) The origin of the gemstone: indicates whether the gemstone is natural, synthetic, imitation or composite, whether it has been optimized and the method of treatment.
(3) Gemstone color: Describe the color of the gemstone (including color, brightness and saturation), as well as the color distribution characteristics.
(4) Gem clarity: Describe the clarity characteristics of colored gems.
(5) Cut type: Describe the cut type and characteristics of the gem.
(6) Carat weight: Indicate the actual weight of the stone, and indicate whether it is directly weighed or measured, using the formula to estimate the weight.
(7) Stone size: Describe the size of the stone. It is expressed in the form of "minimum diameter x maximum diameter x depth" in millimeters (mm).
(8) Transparency: Describe the transparency characteristics of the gem.
(9) Special optical phenomena: gemstones with special optical phenomena are specifically described.
Pearl
The description usually includes the following aspects:
(1) Genetic type: Describe the genetic type of pearls, that is, whether the pearls are natural or cultured.
(2) Quantity: Whether to evaluate a single pearl or a string of pearls, it is necessary to specify the specific number of pearls.
(3) Size: the diameter of the pearl, the unit of measurement is millimeter (mm).
(4) Shape: the appearance of the pearl shape characteristics.
(5) Color: the pearl's body color and companion color characteristics.
(6) Halo: the surface of the pearl halo characteristics.
(7): the unique characteristics of the pearl surface.
(8) Finish: the degree of smoothness of the pearl surface.
(9) The thickness of the pearl layer: the thickness of the pearl surface.
(10) Other characteristics of pearls: for pearl necklaces, it is necessary to describe the matching of pearls, the length of the bead chain (including the length of the chain), the length of the bead string (excluding the length of the chain), the number, the arrangement, the type of chain link, etc.
jade
The description usually includes the following aspects:
(1) The variety of jade: the name of jade.
(2) Cause: whether the treatment has been optimized and the treatment method.
(3) Style: describe the appearance of jade morphological characteristics, is the original stone, plain surface shape, beads, carved products.
(4) Size: the size and weight of the jade.
(5) Color: jade table and color characteristics, distribution, uniformity.
(6) Structural characteristics: jade particle size, density, uniformity.
(7) Transparency: the transparency (water head) characteristics of jade.
(8) Degree of defects: whether there are cracks, inclusions, etc., in the jade table.
(9) Table and finish: jade table and finish characteristics.
(10) Other features: For jade carvings, it is necessary to describe the underlying art of carving, including carving techniques, work types and themes, designers, producers, etc.