emology Education
1.creating the D-to-Z color scale and Flawless-to-I3 clarity scale for diamonds
2.detecting irradiated yellow diamonds
3.determining the color of black cultured pearls to be natural
4.the first study of a new gem now known as tanzanite
5.the first report on faceted synthetic diamonds
6.identifying Naturl rubies, sapphire ,all type Gems & all type Rudraksha.
7.identifying glass-filled rubies & Gems
8.identifying synthetic & Plastik rubies , Gems & Rudraksha
9.detecting fracture-filled diamonds
10.evaluating the durability of emerald filling substances
11.distinguishing natural from synthetic diamonds
12.detecting synthetic moissanite, a popular diamond imitation
13.identifying the effect of fluorescence on diamond appearance
14.detecting diamonds decolorized by high pressure/high temperature (HPHT) treatment
15.detecting gem-quality synthetic diamonds created by chemical vapor deposition (CVD)
16.creating a comprehensive system for grading diamond cut quality.
17.Specific gravity , Refractive Index , Lustre ,Hardness ,Species ,Chemical , Hardness,
Growth lines , Inclusions , Other characteristics Identify.
How Grades Diamonds
People from all over the world send their diamonds to the Laboratory for grading and analysis.
Grading Diamonds
Anonymity
Objectivity and independence are the hallmarks of all RJL reports and services, and RJL has elaborate processes in place to ensure a diamond anonymity through the grading process.
Weights and Measures
Diamonds are weighed with an electronic micro-balance that captures their weight to the fifth decimal place.
Grading Cut
verify & Grading cut
Grading Color
Since light source and background can have a significant impact on the appearance of color, the diamond color is graded in a standardized viewing environment. Color graders submit their independent opinions into the system.
Grading Clarity and Finish
Clarity is graded with 10x magnification under standard viewing conditions. The preliminary grader carefully examines the diamond to locate clarity/finish characteristics and evidence of any diamond treatments, such as fracture filling or laser drilling.
Depending on the diamond weight, quality, and the agreement of grading opinions, additional quality assurance process steps are also performed. More experienced staff gemologists may review all of the previous grading information and render independent clarity/polish/symmetry opinions. Grading results are finalized once there are sufficient agreeing opinions.
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While diamonds are graded using the system devised by the Gemmological Institute of America (GIA) in the 1950s, there is no standardized or universally accepted grading system for colored stones like rubies, sapphires, emeralds, etc. Historically, it has always been a general practice to grade colored stones with the unaided eye. However, we have devised a grading scale, on the basis of the diamond grading scale, which is easy to understand and not only takes into consideration appearance with the naked eye but also the appearance under 10x magnification (i.e. a jeweler's loupe).
CLARITY GRADING SCALE
Detailed Clarity Grading Scale on the Basis of which the Colored Stones listed in our store are graded (the first one being the best and the last one being the lowest grade)
|
Grade |
Eye-Clean / Loupe-Clean (10x) |
Detailed Description |
|
IF (Internally Flawless) |
Eye-Clean, Completely Loupe-Clean |
No inclusions visible under 10x Magnification |
|
VVS1 (Very Very Slightly Included 1) |
Eye-Clean, Loupe-Clean |
Minor Pin-Point Inclusions visible under 10x Magnification |
|
VVS2 (Very Very Slightly Included 2) |
Eye-Clean, Loupe-Clean |
Minor Pin-Point Inclusions visible under 10x Magnification |
|
VS1 (Very Slightly Included 1) |
Eye-Clean, Near Loupe-Clean |
Minor Inclusions visible under 10x Magnification |
|
VS2 (Very Slightly Included 2) |
Eye-Clean, Near Loupe-Clean |
Minor Inclusions visible under 10x Magnification |
|
SI1 (Slightly Included 1) |
Eye-Clean, Not Loupe-Clean |
Inclusions visible under 10x Magnification but not with unaided eye |
|
SI2 (Slightly Included 2) |
Near Eye-Clean, Not Loupe-Clean |
Inclusions visible under 10x Magnification and also with unaided eye (minor) |
|
SI3 (Slightly Included 3) |
Not Eye-Clean, Not Loupe-Clean |
Inclusions visible under 10x Magnification and also with unaided eye (considerable) |
|
I1 (Included 1) |
Visibly Included |
Inclusions visible under 10x Magnification and also with unaided eye (heavy) |
|
I2 (Included 2) |
Visibly Included |
Inclusions visible under 10x Magnification and also with unaided eye (very heavy) |
|
Semi-Transparent |
Varies from stone to stone |
Not Completely Transparent neither Completely Translucent |
|
Milky-Transparent |
Varies from stone to stone |
Transparent but with milkiness |
|
Translucent |
Varies from stone to stone |
Allowing light to pass through but not transparent |
|
Opaque |
Varies from stone to stone |
Not allowing light to pass through |
Note: The numbers denote the intensity of inclusions i.e. the intensity of inclusions in a stone with VVS2 clarity would be more than those in a stone with VVS1 clarity.
GENERAL GRADING SCALE
Gemstones are also graded on a scale from “A” to “Z” by our gemmologists based on the overall appearance and after taking into consideration the combination of the following criteria:
This is a general grading scale which divides all gemstones into parts depending on a variety of factors. A Majority of the stones listed on the store are grade “A” and grade “B” stones since we list very few grade “C’, “D” , “E” stones etc.
Also See: Gem Certification
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Gem Testing Reports
Gemological Identification Reports assess the characteristics of a Astro-Gem (weight, shape-cut ,Transparency,Lustre, Refractive Index,Specific gravity , Hardness ,Species, Inclusions and color) and indicate any detectable treatments. The stone’s identity, whether it is natural or synthetic, and if it is a ruby, sapphire or emerald ect., geographic origin is provided.
Gem Identification Reports
These reports document the results of a full gemological examination of a material, identifying the material examined and detailing such characteristics as color, transparency, shape, cut, and dimensions weight . The full report states whether the material is natural or synthetic and if it has been treated to enhance its appearance by an identifiable treatment. The report also notes whether the material is a simulant with no known natural counterpart, or if it has been assembled from two or more separate components.
|
Gemstone Name |
Specific Gravity |
Mohs Hardness |
Index of Refraction |
Gemstone Family |
|
Achorite |
3.03 - 3.25 |
7.0 - 7.5 Mohs |
1.610-1.661 |
Tourmaline
|
|
Agate |
2.65 |
7.0 Mohs |
1.530 - 1.550 |
Quartz |
|
Almandine |
3.50 - 4.30 |
6.5 - 7.5 Mohs |
1.750 - 1.830 |
Garnet |
|
Almandine Spinel |
3.58 - 4.06 |
8.0 Mohs |
1.708 - 1.735 |
Spinel |
|
Almandine-Spessartine |
3.50 - 4.30 |
6.5 - 7.5 Mohs |
1.750 - 1.830 |
Garnet |
| Amethyst |
2.65 |
7.0 Mohs |
1.532 - 1.554 |
Quartz |
|
Andradite |
3.50 - 4.30 |
6.5 - 7.5 Mohs |
1.880 - 1.940 |
Garnet |
|
Aquamarine |
2.63 - 2.91 |
7.5 - 8.0 Mohs |
1.567-1.590 |
Beryl |
|
Balas Ruby |
3.58 - 4.06 |
8.0 Mohs |
1.708 - 1.735 |
Spinel |
|
Black Opal |
1.98 - 2.25 |
5.5 - 6.5 Mohs |
1.440 - 1.460 |
Opal |
|
Bloodstone |
2.65 |
7.0 Mohs |
1.535 - 1.539 |
Quartz |
|
Brazilian Emerald |
3.03 - 3.25 |
7.0 - 7.5 Mohs |
1.610 - 1.640 |
Tourmaline |
|
Cairngorm |
2.65 |
7.0 Mohs |
1.540 - 1.550 |
Quartz |
|
Carnelian |
2.65 |
7.0 Mohs |
1.530 - 1.550 |
Quartz |
|
Cat’s Eye |
3.68 - 3.78 |
8.5 Mohs |
1.746 - 1.755 |
Chrysoberyl |
|
Chalcedony |
2.65 |
7.0 Mohs |
1.544 - 1.553 |
Quartz |
|
Chlorspinel |
3.58 - 4.06 |
8.0 Mohs |
1.712 - 1.717 |
Spinel |
|
Chrome Pyrope |
3.50 - 4.30 |
6.5 - 7.5 Mohs |
1.730 - 1.760 |
Garnet |
|
Chrysoberyl |
3.68 - 3.78 |
8.5 Mohs |
1.746 - 1.755 |
Chrysoberyl |
|
Chrysoprase |
2.65 |
7.0 Mohs |
1.530 - 1.550 |
Quartz |
|
Citrine |
2.65 |
7.0 Mohs |
1.532 - 1.554 |
Quartz |
|
Color-Change Garnet |
3.50 - 4.30 |
6.5 - 7.5 Mohs |
1.730 - 1.760 |
Garnet |
|
Demantoid |
3.50 - 4.30 |
6.5 - 7.5 Mohs |
1.880 - 1.900 |
Garnet |
|
Diamond |
3.51 |
10 Mohs |
2.417 |
Diamond |
|
Dravite |
3.03 - 3.25 |
7.0 - 7.5 Mohs |
1.610-1.661 |
Tourmaline |
|
Emerald |
2.63 - 2.91 |
7.5 - 8.0 Mohs |
1.560 - 1.605 |
Beryl |
|
Feldspar |
2.55 - 2.76 |
6.0 - 6.5 Mohs |
1.518 - 1.572 |
Feldspar |
|
Fire Opal |
1.98 - 2.25 |
5.5 - 6.5 Mohs |
1.430 - 1.460 |
Opal |
|
Garnet |
3.50 - 4.30 |
6.5 - 7.5 Mohs |
1.730 - 1.760 |
Garnet |
|
Ghanospinel |
3.58 - 4.06 |
8.0 Mohs |
1.712 - 1.747 |
Spinel |
|
Goshenite |
2.63 - 2.91 |
7.5 - 8.0 Mohs |
1.570 - 1.600 |
Beryl |
|
Green Quartz |
2.65 |
7.0 Mohs |
1.540-1.550 |
Quartz |
|
Grossular |
3.50 - 4.30 |
6.5 - 7.5 Mohs |
1.880 - 1.940 |
Garnet |
|
Heliodore |
2.63 - 2.91 |
7.5 - 8.0 Mohs |
1.570 - 1.600 |
Beryl |
|
Heliotrope |
2.65 |
7.0 Mohs |
1.535 - 1.539 |
Quartz |
|
Hessonite |
3.50 - 4.30 |
6.5 - 7.5 Mohs |
1.730 - 1.760 |
Garnet |
|
Hyacinth |
4.60 - 4.70 |
7.5 Mohs |
1.777 - 1.987 |
Zircon |
|
Indicolite |
3.03 - 3.25 |
7.0 - 7.5 Mohs |
1.610 - 1.640 |
Tourmaline |
|
Jade |
2.90 - 3.10 |
6.0 Mohs |
1.640 - 1.667 |
Jade |
|
Jadeite |
3.23 - 3.43 |
6.5 - 7.0 Mohs |
1.640 - 1.667 |
Jade |
|
Jargon |
4.60 - 4.70 |
7.5 Mohs |
1.777 - 1.987 |
Zircon |
|
Jasper |
2.65 |
7.0 Mohs |
1.540 - 1.550 |
Quartz |
|
Labradorite |
2.55 - 2.76 |
6.0 - 6.5 Mohs |
1.560 - 1.572 |
Feldspar |
|
Lapis Lazuli |
2.70 - 2.90 |
5.0 - 5.5 Mohs |
1.500 - 1.550 |
Lapis Lazuli |
|
Malaia |
3.50 - 4.30 |
6.5 - 7.5 Mohs |
1.880 - 1.940 |
Garnet |
|
Matura Diamond |
4.60 - 4.70 |
7.5 Mohs |
1.777 - 1.987 |
Zircon |
|
Moonstone |
2.55 - 2.76 |
6.0 - 6.5 Mohs |
1.518 - 1.526 |
Feldspar |
|
Morganite |
2.63 - 2.91 |
7.5 - 8.0 Mohs |
1.585 - 1.594 |
Beryl |
|
Morion |
2.65 |
7.0 Mohs |
1.540 - 1.550 |
Quartz |
|
Nephrite |
2.90 - 3.10 |
6.0 Mohs |
1.600 - 1.641 |
Jade |
|
Onyx |
2.65 |
7.0 Mohs |
1.531 - 1.539 |
Quartz |
|
Opal |
1.98 - 2.25 |
5.5 - 6.5 Mohs |
1.440 - 1.460 |
Opal |
|
Orthoclase |
2.55 - 2.76 |
6.0 - 6.5 Mohs |
1.518 - 1.526 |
Feldspar |
|
Peridot |
3.22 - 3.45 |
7.0 Mohs |
1.635 - 1.690 |
Peridot |
|
Peristerite |
2.55 - 2.76 |
6.0 - 6.5 Mohs |
1.560 - 1.572 |
Feldspar |
|
Praziolite |
2.65 |
7.0 Mohs |
1.540 - 1.550 |
Quartz |
|
Pyrope |
3.50 - 4.30 |
6.5 - 7.5 Mohs |
1.730 - 1.760 |
Garnet |
|
Pyrope-Almandine |
3.50 - 4.30 |
6.5 - 7.5 Mohs |
1.730 - 1.760 |
Garnet |
|
Pyrope-Spessartine |
3.50 - 4.30 |
6.5 - 7.5 Mohs |
1.730 - 1.760 |
Garnet |
|
Quartz |
2.65 |
7.0 Mohs |
1.544 - 1.553 |
Quartz |
|
Red Beryl |
2.63 - 2.91 |
7.5 - 8.0 Mohs |
1.570 - 1.598 |
Beryl |
|
Rhodolite |
3.50 - 4.30 |
6.5 - 7.5 Mohs |
1.740 - 1.770 |
Garnet |
|
Rock Crystal |
2.65 |
7.0 Mohs |
2.000 |
Quartz |
|
Rose Quartz |
2.65 |
7.0 Mohs |
1.540 - 1.550 |
Quartz |
|
Rubellite |
3.03 - 3.25 |
7.0 - 7.5 Mohs |
1.610 - 1.640 |
Tourmaline |
|
Rubicelle |
3.58 - 4.06 |
8.0 Mohs |
1.712 - 1.717 |
Spinel |
|
Ruby |
3.96 - 4.05 |
9.0 Mohs |
1.757 - 1.779 |
Corundum |
|
Sapphire |
3.96 - 4.05 |
9.0 Mohs |
1.757 - 1.779 |
Corundum |
|
Sapphire Spinel |
3.58 - 4.06 |
8.0 Mohs |
1.712 - 1.747 |
Spinel |
|
Siberite |
3.03 - 3.25 |
7.0 - 7.5 Mohs |
1.625-1.675 |
Tourmaline |
|
Smoky Quartz |
2.65 |
7.0 Mohs |
1.540 - 1.550 |
Quartz |
|
Spessartine |
3.50 - 4.30 |
6.5 - 7.5 Mohs |
1.790 - 1.810 |
Garnet |
|
Spinel |
3.58 - 4.06 |
8.0 Mohs |
1.712 - 1.717 |
Spinel |
|
Sunstone |
2.55 - 2.76 |
6.0 - 6.5 Mohs |
1.560 - 1.572 |
Feldspar |
|
Topaz |
3.50 - 3.60 |
8.0 Mohs |
1.607 - 1.627 |
Topaz |
|
Topazolite |
3.50 - 4.30 |
6.5 - 7.5 Mohs |
1.880 - 1.940 |
Garnet |
|
Tourmaline |
3.03 - 3.25 |
7.0 - 7.5 Mohs |
1.603 - 1.655 |
Tourmaline |
|
Tsavorite |
3.50 - 4.30 |
6.5 - 7.5 Mohs |
1.739 - 1.744 |
Garnet |
|
Turquoise |
2.60 - 2.80 |
5.0 - 6.0 Mohs |
1.610 - 1.650 |
Turquoise |
|
Uvarovite |
3.50 - 4.30 |
6.5 - 7.5 Mohs |
1.740 - 1.870 |
Garnet |
|
Verdilite |
3.03 - 3.25 |
7.0 - 7.5 Mohs |
1.612-1.638 |
Tourmaline |
|
Water Opal |
1.98 - 2.25 |
5.5 - 6.5 Mohs |
1.440 - 1.460 |
Opal |
|
White Opal |
1.98 - 2.25 |
5.5 - 6.5 Mohs |
1.440 - 1.460 |
Opal |
|
Zircon |
4.60 - 4.70 |
7.5 Mohs |
1.777 - 1.987 |
Zircon |