Gemstone Certificate Reports

 

What is a gemstone report?

 

A gemstone certificate determines the quality of a gemstone. It details all key elements that measure the stone’s quality, and whether it is authentic or fake.

The key factors in the report may vary slightly from one laboratory to the other due to the different technologies used, but the basic foundations remain the same, and are based on scientific analysis and accepted criteria worldwide.

A typical gemstone report has a picture of the gem on one side and its details on the other. 

 

Key factors examined in most gemstone reports

 

The basic factors that are examined are authenticity, carat weight, shape & cut, color, dimensions, optic character, specific gravity, refractive index & hardness, and type. Comments are added the report to cover other tests.

 

Aspects examined in the report:

  1. Report No.

The report number is used for future identification when you need to obtain a copy of the report from the laboratory.

 

  1. Date

Date of  testing.

 

  1. Type of stone

There are many types of gemstones, including:

Sapphire, emerald, ruby, jade, amber, pearl, lapis, rose quartz, turquoise, moonstone, opal, topaz, carnelian, agate, onyx, malachite, tourmaline, tiger’s eye, pyrite, citrine, peridot, labradorite, tanzanite, alexandrite, jasper, aquamarine, fluorite, aventurine, zircon, morganite, nephrite, amazonite, spinel, sodalite, chalcedony, smoky quartz, heliotrope, beryl, sunstone, rhodonite, larimar, kyanite, serpentine, rhodochrosite, chrysoprase, chrysocolla, titanite, ametrine.

 

  1. Color

Color measurement is the most variable factor and most difficult to measure. In most systems, the basic hues are red (R), orange (O), yellow (Y), green (G), blue (B), violet (V), and purple (P). Brown, white, and black are not considered hues, but tone and saturation.

For gems with multiple hues, the primary hue appears last and the modifier first. For example, “greenish yellow” means a hue with more yellow than green and is expressed with abbreviations, with the primary color capitalized – gY.

For tone values, the first number in the color grading code represents the tone, ranging from 0 (colorless or white), to 10 (black). This number represents the relative brightness or darkness of the gem. For example, a gem graded “slpR 3/4” has a tone of 3, a light tone. The second number represents the saturation of the gem’s hue, ranging from 1 to 6. Warm hues, such as red, orange, and yellow, become shades of brown as their saturation decreases. Cool hues, like blue and violet, become grayer as their saturation decreases.

For warm colors, 1 represents the warmest hue, and 6 represents the most vivid hue. For cool colors, 1 represents grayish, and 6 represents vivid. Vivid levels of saturation are rare, and are found mainly in rubies and sapphires.

 

  1. Weight

As in diamonds, the total weight of the gemstone is measured in carats. 

 

  1. Description

This section indicates whether the gemstone is mounted (on a ring) or unmounted. Gemstones are normally certified before mounting.

 

  1. Shape & Cut

For gemstones, the types of cut include oval, round, or mix. 

 

  1. Dimensions

The size of the gemstone – width, length.

 

  1. Transparency

The transparency of a gemstone is the degree to which the light passes through the gemmiferous  material.  It is graded as follows:

  • Transparent: You can see objects through the gemstone clearly.
  • Semi-transparent: You can see blurry objects through the gemstone.
  • Translucent: The objects are hardly visible, but light is still transmitted through the gemstone.
  • Semi-translucent: Only a small amount of light is transmitted through the gemstone.
  • Opaque: Light does not pass through the gemstone.
  1. Other Tests

This section includes additional tests such as IR spectra analysis, microscopic observation, and more.

 

  1. Comments 

If the stone was subjected to heat or treated with a particular chemical, this will be mentioned in the comments. 

 

  1. Seal of trust and authenticity

The report is signed and verified by the laboratory to certify its authenticity.

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