Gemology.docx

http://basilgemlab.com/

Services Accurate identification is essential in maintaining the commercial value of gemstones. It is also a required skill which enables jewelers to disclose to their customers the correct identity of the gemstones they sell.

By using standard gem testing instruments and techniques, trained gemologists can recognize most gem materials.

In some instances, gemologists may not be able to distinguish certain synthetic and laboratory treated gem materials using standard gem testing instruments , which can have almost the same visual appearance and gemological properties as their natural counterparts.

With a sound knowledge on the help of inclusions

Separation of natural from synthetic gemstones

Identification and disclosure of treatments on coloured stones

1.Report Number Each report bears a unique 14 digit number, B230316AB18361. This individual document number is critical to substantiate a reports’ authenticity.

2.Date The date on the report identifies the date when the item was certified at our laboratory.

3.Object Description

A brief description identifies the Gemstone being tested; e.g. “One faceted gemstone” or “Ring with 5 facetted stones”.

4.Shape / Cut Describes both the shape (girdle outline) and the cut of the Gemstone. Shapes can be round, oval, etc Cut refers to the facet pattern, e.g. brilliant cut, step cut.

5.Weight in Carats The carat (ct) is a unit of mass equal to 200 mg (0.2 g) and is used for measuring gemstones

6.Measurments

For many shapes, 3 measurements are needed to ensure a gemstone will fit a jewelry mounting. For example: An oval 6 mm x 4 mm x 3 mm gemstone, would be6 mm in length, 4 mm in width, and 3 mm in depth. For round or square gems, only two measurements are needed since the length and width are the same (or very close)

7.Color/Transparency Colour ) is the characteristic of human visual perception described through color categories, with names such as red, blue, yellow, green, orange, or purple. This perception of color derives from the stimulation of cone cells in the human eye by electromagnetic radiation in the spectrum of light. Color categories and physical specifications of color are associated with objects through the wavelength of the light that is reflected from them. This reflection is governed by the object's physical properties such as light absorption, emission spectra, etc gemstone transparency – whether agem is opaque, translucent, or transparent – is a result of light interacting with the gem

8.Refractive Index A ratio, which indicates the ‘optical density’ of a substance. It is related to the angles of incidence and refraction of light. The refractive index is different for most gem-species.

9.Optic Character An optical instrumentpolariscope used in testing transparent gemstones to distinguish between isotropic and anisotropic materials.

10.Specific Gravity (SG) Specific Gravity (SG) is the ratio of the weight of a substance to the weight of an equal volume of water. Every gem has its own specific gravity and the SG can be used as an additional value in gemstone identification. For this, a hydrostatic balance is used.

11.Hardness Hardness of a gemstone is its resistance to scratching and may be described relative to a standard scale of 10 minerals known as the Mohs scale. F. Mohs, an Austrian mineralogist, developed this scale in 1822

9.Optic Character An optical instrumentpolariscope used in testing transparent gemstones to distinguish between isotropic and anisotropic materials.

10.Specific Gravity (SG) Specific Gravity (SG) is the ratio of the weight of a substance to the weight of an equal volume of water. Every gem has its own specific gravity and the SG can be used as an additional value in gemstone identification. For this, a hydrostatic balance is used.

11.Hardness Hardness of a gemstone is its resistance to scratching and may be described relative to a standard scale of 10 minerals known as the Mohs scale. F. Mohs, an Austrian mineralogist, developed this scale in 1822

Microscopic examination

10.Specific Gravity (SG) Here we observe carefully the inclusions through the GIA Microscope for synthetic inclusions,shape of the inclusion deviated from natural origin(treated) and confirm the authenticity of gemstone.

Identification

Examined stones of natural formation, are identified as Natural before the Gemstone name. Gemstones produced from a synthetic crystal, will bear the term Synthetic in front of the name (e.g. Synthetic Ruby). Stones that have undergone rigorous treatment will be marked as enhanced in the comments (e.g. Thermally Enhanced).