Gemstone Weight Converter
Carats, rattis, grams, points & milligrams — plus physical size estimation
Gemstone Weight Converter
| Unit | Value |
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Gemstone Size Estimator
Estimate physical diameter from carat weight for round stones
Weight
Est. Diameter
round cut
In Rattis
Indian unit
Diamond Carat Size Reference
Approximate face-up diameter for round brilliant cut diamonds
* Based on ideal cut proportions. Actual measurements may vary by ±5% depending on cut quality.
Ratti vs Carat — The Indian Market Difference
Ratti (Indian Traditional)
Carat (International Standard)
When buying gemstones in India, ask for both the ratti and carat weight. Astrological recommendations are often in rattis, but certificates (GIA, IGI) use carats. Use this converter to verify you are getting the right weight in both systems.
Typical Price Range for Common Indian Gems
Indicative retail market ranges — actual prices vary widely by quality, origin, and treatment
| Gemstone | Price Range / Carat | Price Range / Ratti | Notes |
|---|---|---|---|
| Ruby (Manik) | ₹3,000 – ₹2,00,000 | ₹1,800 – ₹1,20,000 | Burmese unheated commands premium |
| Emerald (Panna) | ₹2,000 – ₹1,50,000 | ₹1,200 – ₹90,000 | Colombian origin most valued |
| Blue Sapphire (Neelam) | ₹5,000 – ₹5,00,000 | ₹3,000 – ₹3,00,000 | Kashmir origin extremely rare |
| Yellow Sapphire (Pukhraj) | ₹1,500 – ₹1,00,000 | ₹900 – ₹60,000 | Sri Lankan (Ceylonese) preferred |
| Pearl (Moti) | ₹300 – ₹50,000 | ₹180 – ₹30,000 | South Sea & basra most valuable |
| Diamond | ₹25,000 – ₹10,00,000+ | ₹15,000 – ₹6,00,000+ | Varies heavily by 4Cs |
| Hessonite (Gomed) | ₹200 – ₹15,000 | ₹120 – ₹9,000 | Ceylonese orange-brown variety |
| Cat's Eye (Lehsunia) | ₹500 – ₹40,000 | ₹300 – ₹24,000 | Chrysoberyl with strong chatoyancy |
Prices are indicative as of early 2026. Untreated, certified stones command a significant premium. Always buy with a reputed lab certificate (GIA, IGI, GRS, Gübelin).
Frequently Asked Questions
1 carat = 0.2 grams and 1 ratti = 0.1215 grams. So 1 carat = 0.2 / 0.1215 = approximately 1.646 rattis. Conversely, 1 ratti = about 0.6075 carats. A 5-ratti ruby weighs about 3.04 carats (0.6075 × 5).
A point is 1/100th of a carat, equal to 0.01 carats or 0.002 grams. Smaller diamonds are described in points: a 50-point diamond is 0.50 carats, a 75-point is 0.75 carats. Points are only used in the diamond trade.
The tool gives an approximate diameter assuming ideal proportions. Real-world accuracy is ±5–10% because cut depth ratios vary. A 1-carat diamond with 62% depth will measure differently from one at 59% depth despite identical weight. Use the diamond size reference table for benchmarks.
Different gems have different densities (specific gravity). A 1-carat diamond (density 3.51) measures ~6.4mm, but a 1-carat emerald (density 2.71) measures ~6.9mm because emerald is lighter per volume — you get more volume for the same weight. Sapphire is denser than diamond, so it looks smaller per carat.
Always verify with carats and a GIA/IGI certificate for significant purchases. While local dealers quote rattis, certificates use carats. Use this converter to cross-check. For astrological stones (jyotish ratna), astrologers prescribe in rattis — convert to carats to verify you received the correct weight.