Colour Grading  >> http://www.GanpatiJewelsJaipur.com GIA colored gemstone grading system The same "four Cs" that establish quality in Diamond are used for colored gemstones: cut, carat weight, clarity and most importantly, color. Color: The more pure and vivid the color, the more valuable the gemstone. Cut: All gemstones must be cut well to attain their maximum potential for beauty. Quality cutting is what produces the brilliance and scintillation that captures the eye of the beholder. Clarity: Gemstones contain characteristic inclusions that provide proof of their natural origin. Those inclusions should not be so visible that they detract from the beauty of the gemstone. Carat Weight: Obviously, larger gemstones are more rare. However, some gemstones, such as Amethyst and Tourmaline, routinely occur in very large sizes while others, such as Ruby and Sapphire, rarely occur in sizes above 2 to 3 carats.

COLOR: Considered the most important. Each gemstone has its own specific colors, and each has its most desired color which will vary from one geographic area to another. Generally the richer (darker, but not too dark) and brighter the color and the more even color distribution, the prettier and more expensive the gemstone will be. The duller, more zoned and lighter colored gemstone will usually be more reasonable. Color grade can be 70% of the total value of the gemstone. Hue: The essential impression of color that we notice immediately (Red, Blue, Greenish Yellow, etc) Tone: The color's lightness or darkness. (Light, Medium, Dark) Saturation: Purity of the color. The more grayish or brownish, the lower the saturation and the duller the color. Gemstones that have real dark tone, or real light one (washed out) never reach a high saturation. The desired appearance is appealing and bright and could be called "Vivid". Vivid-Bright (6)  5         Medium (4-3)  2     Dull Brown-Gray (1) CUT: (Quality/Polish/Finish) - Excellent (10 - 8) Very Good (7 - 6) Good (5 - 4) Fair (3 - 1) CLARITY: The degree of freedom from visible characteristics put there by Mother Nature during the stone's growth. Clarity grades for colored gemstones are categorized into three areas: Type I that are generally very clean and are penalized more than Type II for having any inclusions and Type III, where inclusions are expected and not penalized as heavily as Types I & II. Type I Aquamarine, Chrysoberyl, Citrine, Topaz, Smoky Quartz, Green Tourmaline, Tanzanite and Blue Zircon. Type II Alexandrite, Amethyst, Garnets, Peridot, Iolite, Ruby, Sapphire, Spinel, all Tourmaline except red and green. Type III Emeralds, Red & Pink Tourmalines. VVSI - Very, Very Slightly Included (the best) Minute inclusions that are difficult to see using 10X, and are not visible at all to the naked eye. VSI - Very Slightly Included Minor inclusions that are easier to see using 10X, but still not visible to the naked eye. SI1 - Slightly Included I The inclusions are easily seen using 10X, and are noticeable with the naked eye. SI2 - Slightly Included 2 The inclusions are more easily seen using 10X, and are quite visible with the naked eye. I1 - Included 1 The inclusions are very obvious and they have a moderate negative effect on the over-all appearance or durability of the gemstone. I2 - Included 2 The inclusions are very obvious and they have a severe negative effect on the over-all appearance or durability of the gemstone. I3 - Included 3 The inclusions are very obvious and they have a severe negative effect on both the over-all appearance and durability of the gemstone. Declasse - stones not transparent because of inclusions   COLOR & CLARITY GRADING COLOR CLARITY Extra Fine (10 - 9) Top known color for its variety Even distribution-optimal tone & vivid Type I Flawless under 10x   II Very slightly included under 10x   III Not included to the eye   Fine  (8 to 7) Highly desirable - strong saturation Type I Very slightly included under 10x   II Slightly included under 10x   III Very slightly included to the eye     Good  (6 to 4) Desirable - some zoning Some extinction - Moderate saturation Type I Slightly included under 10x   II Included under 10x becoming visible to the eye   III Slightly included to the eye   Commercial (3 to 1) Fair to Good Heavy Zoning & Extinction Gray or brown saturation Type I Heavily included under 10x   II Visible inclusions to the eye   III Included to the eye Gemstone quality grading at Ganpati jewels are drived from above described colored gemstone grading system of GIA Below mentioned scale define Clarity, Color ,Cutting & Overall Quality Grading At Ganpati jewels. Clarity Clarity Scale  VVSI1 VVSI2        VSI1     VSI2 SI1 SI2 I1 I2 I3     very slight Inclusions 1 very slight Inclusions 2 Slight Inclusions 1 Slight Inclusions 2 Included 1 Included 2 Severely included   Color Color Scale AAA AA A LS VLS Excellent Very Good Good Light Shade Very Light Shade   Cutting and Finishing Cutting and Finishing Scale 10-9 8-7 6-4 3-1 0 Super Fine Very Good Good Fair Poor   Overall Quality Grading Below is scale, which defines Overall Quality of Gemstone and Beads at Ganpati Jewels Quality Grading Scale AA A               AB B C DCl Super Fine Quality Vary Good Quality     Good Quality Average Quality Low Quality Very Low Quality