Cow Shelter/Donation
The Divine Hindu App is here.
Chat free with top astrologers for your first 5 minutes every week, generate your Kundli, book temple Puja & Chadhava, and check today's Panchang — all in one app.
TL;DR — The familiar rule of thumb is about one ratti of stone for every 10 to 12 kilograms of body weight — so a 60 kg person lands somewhere between 5 and 6 ratti, which is roughly 4.5 to 5.5 carats. It is a trade convention, not a scriptural rule, which is exactly why practitioners give different answers and why the range is so wide. The tradition itself puts more emphasis on the quality of the material than on hitting a number. This guide covers the rules of thumb and why they vary, the nine ratna and the grahas they are traditionally associated with, the difference between jyotish-grade and jewellery-grade stones, treated versus untreated material, and what a gem certificate actually certifies. Gemstones are worn as a matter of tradition and personal faith. We make no health, medical or wealth claims of any kind, and nothing here replaces professional advice.
"How many ratti should I wear?" is the question we are asked most often, and it deserves a more honest answer than it usually gets.
The honest answer is that there is no single traditional rule. The formulas in circulation are conventions of the Indian gem trade, refined over generations of practice and handed on from teacher to student, and they differ from one lineage to the next because they were never written down as a single standard in the first place. That is worth knowing before you accept any number as authoritative — including ours.
What this guide does is set out the conventions that actually circulate, explain why they disagree, and then do the practical part: turn whatever number you have been given into a weight you can check against a listing or a certificate. That last step is where our Ratti Carat Converter and our companion guide, Ratti to Carat: How Gemstone Weight Is Measured in India, come in.
One thing stated plainly at the top and repeated below, because it matters. Gemstones in the Vedic tradition are worn as a matter of custom and personal faith. We do not claim, and you should not accept from anyone, that a stone cures, heals, treats, prevents or improves any medical condition, or that it produces money, luck, career outcomes or marital results. Nothing on this page is medical, legal, financial or relationship advice, and nothing here should displace a qualified professional.
The body-weight rule of thumb, and why it varies
The convention most widely repeated in the Indian trade is simple arithmetic:
roughly 1 ratti of stone per 10–12 kg of body weight
You will find both the 10 and the 12 in wide use, which already tells you something. Here is what the two produce across a range of body weights, with the carat equivalent worked out using the pakki ratti of 182.25 mg against the metric carat of 200 mg.
| Body weight | At 1 ratti per 10 kg | At 1 ratti per 12 kg | Approximate carat range |
|---|---|---|---|
| 50 kg | 5.0 ratti | 4.2 ratti | ≈ 3.8 – 4.6 ct |
| 60 kg | 6.0 ratti | 5.0 ratti | ≈ 4.6 – 5.5 ct |
| 70 kg | 7.0 ratti | 5.8 ratti | ≈ 5.3 – 6.4 ct |
| 80 kg | 8.0 ratti | 6.7 ratti | ≈ 6.1 – 7.3 ct |
| 90 kg | 9.0 ratti | 7.5 ratti | ≈ 6.8 – 8.2 ct |
Look at the spread. At 70 kg the two versions of the same rule differ by well over a carat. That is not a rounding difference — on a fine stone it is a substantial difference in price. So why does the rule vary at all?
Because it is not in the classical texts. This is the part most articles will not tell you. The Sanskrit ratna-shastra literature discusses gemstones at length — their species, their qualities, their flaws, their association with the grahas — but it does not lay down a body-weight formula. The formula is a modern trade convention. It is a useful one, it is widely honoured, and it has the great virtue of scaling sensibly, but it does not carry scriptural authority and nobody should present it as though it does.
Because different lineages teach differently. Some practitioners scale by body weight; some work from the strength of the relevant graha in the chart; some prescribe a customary minimum for each stone regardless of the wearer; some simply give the number their own teacher gave. All of these are internally coherent traditions.
Because availability shapes advice. This is the uncomfortable one and it should be said. Certain ratti weights are easier to source and easier to sell, and a recommendation is sometimes shaped by what a supplier can readily provide. It is a fair question to ask why a particular number was chosen.
The customary quarter
You will notice that recommendations rarely land on round numbers. 3.25, 5.25, 7.25, 9.25 — the extra quarter ratti is a strong convention in the Indian trade, and round figures are widely avoided. There is no classical requirement behind it; it is a habit of practice, and a harmless one. If your recommendation came with a quarter attached, that is why.
What the tradition emphasises instead
Read the older material and the emphasis falls somewhere else entirely: on the quality of the stone. Colour, transparency, the absence of specific flaws, whether the material is natural — these are what the ratna literature actually discusses in detail. The consistent view in the tradition is that a smaller stone of good material is preferred to a larger one of poor material, and practitioners who take the texts seriously tend to say the same thing today.
If your budget forces a choice between size and quality, the tradition is clear about which way to go.
The nine ratna and the grahas they are associated with
The navaratna — nine gems — are the stones traditionally assigned one to each of the nine grahas of Vedic astrology. The associations below are the standard ones. They describe which graha a stone is traditionally linked to, and nothing more; no outcome is claimed for wearing any of them.
| Graha | Stone | Indian name | Species / material |
|---|---|---|---|
| Sun (Surya) | Ruby | Manik / Manikya | Corundum |
| Moon (Chandra) | Pearl | Moti | Organic — nacre |
| Mars (Mangal) | Red coral | Moonga | Organic — coral skeleton |
| Mercury (Budha) | Emerald | Panna | Beryl |
| Jupiter (Guru) | Yellow sapphire | Pukhraj | Corundum |
| Venus (Shukra) | Diamond | Heera | Carbon |
| Saturn (Shani) | Blue sapphire | Neelam | Corundum |
| Rahu | Hessonite garnet | Gomed | Grossular garnet |
| Ketu | Cat's eye | Lehsunia | Chrysoberyl |
Three of the nine — ruby, yellow sapphire and blue sapphire — are all corundum, the same mineral species in three colours. Two are organic rather than mineral: pearl is nacre laid down by a mollusc, and red coral is the skeleton of a marine organism. This matters practically, because organic materials are softer, more porous and need different care from a sapphire.
Our fuller treatment of the set is in the navratna guide to the nine gems, and the sign-by-sign associations are collected in the rashi stone chart for all twelve signs. You can also browse by sign at shop by rashi.
Uparatna: the substitute stones
Alongside the nine principal ratna, the tradition recognises uparatna — secondary or substitute stones, one or more for each graha, traditionally used where the principal stone is out of reach. Yellow topaz or citrine for Pukhraj, amethyst or blue topaz for Neelam, peridot or green tourmaline for Panna, red jasper or carnelian for Moonga are among the common substitutions.
Two points worth making. First, this is a genuine part of the tradition, not a modern invention — the practice of substitution appears in the older material. Second, an uparatna is a different mineral from the ratna it stands in for and should be sold and described as what it is. A citrine is a citrine; if it is being offered to you as a Pukhraj, that is a misdescription, and no traditional argument makes it acceptable.
Jyotish grade and jewellery grade: what the difference actually is
You will see "jyotish quality" and "astrological grade" used constantly in this market. It is worth being clear about what those terms do and do not mean.
They are trade terms, not defined standards. There is no laboratory that certifies a stone as "jyotish grade", no governing body that publishes the specification, and no scriptural definition that maps onto it. Different dealers use the phrase to mean somewhat different things. Treat it as a claim to be unpacked, not a grade to be trusted.
That said, the criteria that serious dealers are usually pointing at when they use the phrase are real and checkable:
| Criterion | What is usually meant | How you verify it |
|---|---|---|
| Natural origin | Formed in the earth, not grown in a laboratory. Practitioners generally hold that only natural material carries the traditional association. | The identification line on a gem lab report: "natural" versus "synthetic" or "laboratory-grown". |
| Untreated | No heating, filling, oiling, diffusion or irradiation. Many practitioners hold that untreated material is required for traditional use. | The comments or treatment line on the report. |
| Clean to the eye | Free of the specific flaws — cracks, cloudiness, black inclusions — that the ratna literature names as defects. | Ten-times loupe, good light, and the clarity comments on the report. |
| Good colour and transparency | Even, saturated colour and clear transmission of light, which the classical material prizes above size. | Your own eyes in daylight, and photographs taken in neutral light. |
| Adequate weight | Enough carat weight to meet the recommendation given. | The weight line on the report; convert it with our converter page. |
Jewellery grade, by contrast, is material selected for how it looks set into a piece. It will usually be treated — because the overwhelming majority of commercial corundum and emerald on the market is — and it may be calibrated to standard millimetre sizes for mass-produced settings. That is entirely legitimate material, sold openly for what it is. It is simply selected on different criteria.
The practical consequence: an untreated, natural, eye-clean stone of a decent size in one of the nine ratna species is a genuinely scarce object, and it is priced accordingly. If a listing offers you a large, clean, untreated natural blue sapphire at a price that seems too good, the sensible response is to look very carefully at the report rather than at the photograph.
Treated versus untreated
Almost all coloured stone on the world market has been treated in some way. This is normal, long-established and legal, and the issue is not treatment itself but disclosure. Here are the treatments you will actually meet in the nine ratna.
| Treatment | Applied to | What it does |
|---|---|---|
| Heat treatment | Ruby, blue and yellow sapphire | Sustained high temperature to improve colour and clarity. The most common treatment in corundum by a wide margin, and stable. |
| Oiling / resin filling | Emerald | Filling surface-reaching fractures to reduce their visibility. Near-universal in emerald; laboratories grade the degree from None to Significant. |
| Lead-glass filling | Ruby | Filling fractures with high-lead glass. Substantially alters the apparent quality, is not durable, and materially affects value. |
| Diffusion | Sapphire | Introducing elements such as beryllium at high temperature to change colour, sometimes only in a surface layer. |
| Irradiation | Various, including some diamonds and topaz | Altering colour by exposure to radiation, usually followed by heating. |
| Bleaching / dyeing | Pearl, coral | Lightening or colouring organic material. Common enough that it should always be asked about. |
Laboratories are expected to detect and disclose these, and the treatment line is one of the first things to look for on a report. Its absence is not a clean bill of health — it may simply mean the question was not addressed. Ask.
For the traditional cautions about who is customarily advised not to wear which stone, see our guide to the traditional cautions around gemstones. Those are matters of custom, not of health.
What a certificate certifies — and what it does not
A gem laboratory certificate is a technical report on one specific stone. It records the weight in carats, the dimensions in millimetres, the identification of the species, whether the material is natural or synthetic or an imitation, and any detectable treatments. Some laboratories add geographic origin for stones where origin affects value. Every report carries a number you can check against the issuing laboratory.
What a certificate does not do is certify that a stone will produce any effect at all. No laboratory in the world tests for that, and any document implying otherwise is not a gemmological report.
The distinction that gets muddled: government certification
This needs to be stated precisely, because the two phrases are used loosely in the Indian market and the conflation genuinely misleads people.
A gem lab certificate and a government laboratory certification are different instruments issued for different purposes. At Divine Hindu, government laboratory certification applies to our Karungali (Ebony) products only. It is not a claim we make about gemstones, and it should not be read across to them. Our gemstones carry their own gemmological documentation where that documentation exists, and that documentation says what it says: species, natural or synthetic, weight, dimensions, treatment.
If any seller describes a coloured stone to you as "government certified", ask them which specific document they mean, who issued it, and what it states. It is an entirely reasonable question and a straight answer should be easy to give.
Converting your recommendation into something you can check
You have been given a number in ratti. The listing in front of you is in carats. Here is the whole of the arithmetic.
A metric carat is exactly 200 milligrams — that value is fixed by international agreement and never varies. The ratti is not fixed. For astrological gemstones the intended measure is normally the pakki ratti of about 182.25 mg, though a great many sellers round it to a flat 180 mg. So:
- 1 ratti ≈ 0.91 carat (0.90 if the seller rounds to 180 mg)
- 1 carat ≈ 1.10 ratti (1.11 on the rounded figure)
- A quick mental check: ratti and carat are close to one-to-one, then correct by about a tenth. Five ratti is near 4.5 carats.
The trap to avoid is the kacchi or goldsmith's ratti of about 121.5 mg, which is 50% lighter and is used for gold rather than gemstones. If a quoted ratti figure looks far off the one-to-one-minus-a-tenth rule, that is often what has happened. The full explanation, including where all these values come from, is in Ratti to Carat, and you can work through any individual case on the Ratti Carat Converter.
Check the weight you have been quoted
Work through the carat, gram and ratti figures on any listing before you buy — ours or anyone else's.
Open the Ratti Carat Converter →A practical checklist before you buy
- Get the recommendation in writing, with its basis. Which stone, what weight, and on what reasoning — body weight, chart, or customary minimum.
- Convert it to carats. Compare like with like. A price per carat is comparable across sellers; a price per ratti is only comparable if both use the same ratti.
- Read the identification line first. Natural, synthetic or imitation. Nothing else on the report matters until this is settled.
- Read the treatment line second. If it is absent, ask.
- Verify the report number with the issuing laboratory. An unverifiable certificate is a piece of paper.
- Check the dimensions, not only the weight. Density and cut mean two stones of identical carat weight can look quite different set in a ring.
- Do not overshoot on size at the cost of quality. The tradition prefers a smaller good stone; so, generally, does resale.
- Ask about the setting. Traditional practice pays attention to the metal and to the stone touching the skin — customs differ, and our guide to which finger to wear which gemstone covers the usual conventions.
- Keep expectations where they belong. A gemstone is worn as tradition and personal faith. It is not a treatment, not a remedy and not a financial instrument.
Stone-by-stone reading
For detail on individual ratna — their species, what to look for, and the traditional associations — see our guides to Pukhraj (yellow sapphire), Neelam (blue sapphire), Panna (emerald) and Moonga (red coral). If you have not yet had a chart read and are working out which graha is even in question, start with How to Read Your Kundli; if the occasion is a marriage, Kundli Milan: the 36 gunas of Ashtakoot sets out what that process does and does not cover.
A closing note on expectations
We sell gemstones, so we have an obvious interest in your buying one. That is exactly why this section is here.
A gemstone in the Vedic tradition is worn as an act of faith and cultural continuity. It is a beautiful natural object with a long place in Indian custom, and for many people that is meaning enough. It is not a medicine and makes no difference to any medical condition. It does not generate money, secure a job, resolve a legal matter or fix a relationship. Anyone who tells you otherwise — including anyone selling one — is making a claim they cannot support.
If you have a health concern, see a doctor. If you have a financial or legal question, see the relevant professional. Wear a stone because the tradition means something to you, choose one that is honestly described, and pay a fair price for material that is what it says it is. That is the whole of our advice.
Browse our gemstone collection and the wider all gemstones range, where specifications are stated on each listing, or visit Divine Hindu Store, Jayanagar 3rd Block East, Bengaluru 560011. If anything on a listing is unclear, contact our team with the product link.
Frequently Asked Questions
How many ratti of a gemstone should I wear?
The most widely used trade convention is about one ratti for every 10 to 12 kilograms of body weight, so a 60 kg person lands between roughly 5 and 6 ratti, which is about 4.5 to 5.5 carats. This is a convention of the Indian gem trade rather than a rule found in the classical texts, which is why practitioners give different answers. The tradition itself places more emphasis on the quality of the material than on reaching a particular weight.
Is the body-weight formula for gemstone weight found in the shastras?
No. The Sanskrit ratna literature discusses gemstone species, qualities, flaws and their association with the grahas at length, but it does not set out a body-weight formula. The one-ratti-per-ten-kilograms rule is a modern trade convention. It is widely honoured and scales sensibly, but it carries no scriptural authority and should not be presented as though it does.
Why do different astrologers recommend different weights?
Because there is no single standard. Some practitioners scale by body weight, using either the 10 kg or the 12 kg version of the rule; some work from the strength of the relevant graha in the chart; some prescribe a customary minimum per stone regardless of the wearer; and some pass on the number their own teacher gave. Availability of particular sizes in the market can also shape a recommendation, so it is fair to ask why a number was chosen.
How do I convert a ratti recommendation into carats?
A metric carat is exactly 200 milligrams. For astrological gemstones the intended ratti is normally the pakki ratti of about 182.25 milligrams, though many sellers round it to 180 milligrams. That gives roughly 1 ratti to 0.91 carat, or 0.90 on the rounded figure, and 1 carat to about 1.10 ratti, or 1.11 rounded. As a mental check, treat ratti and carat as close to one-to-one and correct by about a tenth.
What are the nine ratna and which grahas are they associated with?
Ruby for the Sun, pearl for the Moon, red coral for Mars, emerald for Mercury, yellow sapphire for Jupiter, diamond for Venus, blue sapphire for Saturn, hessonite garnet for Rahu and cat's eye chrysoberyl for Ketu. Three of the nine, ruby and yellow and blue sapphire, are all corundum in different colours. Pearl and red coral are organic rather than mineral and need different care. These are traditional associations only; no outcome is claimed for wearing any of them.
What is an uparatna?
An uparatna is a secondary or substitute stone traditionally used in place of one of the nine principal ratna, usually where the principal stone is out of reach. Common examples are yellow topaz or citrine in place of Pukhraj, amethyst or blue topaz for Neelam, peridot or green tourmaline for Panna, and red jasper or carnelian for Moonga. Substitution is a genuine part of the tradition, but an uparatna is a different mineral and must be described and sold as what it actually is.
What does jyotish quality or astrological grade mean?
They are trade terms rather than defined standards. No laboratory certifies a stone as jyotish grade and no governing body publishes a specification. What serious dealers usually mean by the phrase is natural rather than laboratory-grown material, untreated, eye-clean and free of the flaws the ratna literature names, with good colour and transparency. Each of those is checkable on a gem lab report or with a loupe, so ask for the specifics rather than accepting the label.
Are treated gemstones acceptable?
Almost all coloured stone on the world market has been treated in some way, and treatment is normal, long-established and legal. The issue is disclosure rather than treatment itself. Common treatments include heat in ruby and sapphire, oiling or resin filling in emerald, lead-glass filling in ruby, diffusion in sapphire, irradiation, and bleaching or dyeing in pearl and coral. Many practitioners hold that untreated material is preferred for traditional use, so check the treatment line on the report.
What does a gemstone certificate actually certify?
A gem laboratory certificate records the weight in carats, the dimensions in millimetres, the identification of the species, whether the material is natural, synthetic or an imitation, and any detectable treatments. Some laboratories also give geographic origin for stones where origin affects value. It does not certify that a stone will produce any effect, since no laboratory tests for that. Always verify the report number with the issuing laboratory.
Is a gem lab certificate the same as government certification?
No, they are different instruments issued for different purposes. A gem laboratory certificate is a technical report on one stone from a gemmological laboratory. At Divine Hindu, government laboratory certification applies to our Karungali (Ebony) products only and is not a claim we make about gemstones. If a seller describes a coloured stone as government certified, ask which document they mean, who issued it and what it states.
