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 4.6 to 5.5 carats. It is a a practical rule of thumb, not a universal requirement, which helps explain why practitioners give different answers and why the range is wide. Some traditional approaches put 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. Formulas used in the Indian gem trade and by individual practitioners differ. Some advisers follow a teacher or lineage, while others use their own selection criteria. Ask which basis is being used before accepting 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 Weight Guide 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
One practical rule of thumb used by some practitioners 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?
A rule of thumb is not automatically a scriptural requirement. Traditional discussions of gemstones address their species, qualities, flaws and associations with the grahas. That does not by itself establish this body-weight formula as a universal scriptural rule. If an adviser describes an exact weight as prescribed by scripture, ask for the named text, edition and verse, and distinguish that citation from a trade custom or personal recommendation. Use the formula as a practical comparison aid, not proof of an outcome.
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 may encounter recommendations such as 3.25, 5.25, 7.25 or 9.25 ratti. Some practitioners and sellers favour these quarter-ratti increments. Ask why that increment is being recommended in your case, and request the specific text and verse if it is presented as a scriptural requirement. The extra quarter by itself does not establish suitability or efficacy.
What the tradition emphasises instead
Some traditional approaches put emphasis on the quality of the stone. Consider colour, transparency, visible flaws and whether the material is natural. These characteristics can be discussed and checked separately from weight. When comparing a smaller stone with a larger one, look at their actual material, treatments and condition rather than assuming the larger stone is the better choice.
If your budget forces a choice between size and quality, compare the verified material and condition, and choose within your budget rather than chasing a weight alone.
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 are useful. First, some traditions recognise the use of substitute stones; ask your adviser which approach is being followed. 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. The phrase by itself does not establish a standardized laboratory grade or a scriptural specification. Different dealers use it to mean somewhat different things. Ask for the precise criteria and supporting identification report rather than treating the label alone as proof.
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 | Naturally formed, rather than 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. | Inspect without magnification in good light for eye-clean appearance; a ten-times loupe can reveal smaller features. Read any relevant comments actually included in the report. |
| Good colour and transparency | Consistent, rich colour and appropriate transparency for the gem species; assess these separately from weight. | 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 weight guide page. |
Jewellery grade, by contrast, is material selected for how it looks set into a piece. It may be treated — treatments are common in commercial ruby, sapphire and emerald — 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
Many coloured gemstones are treated to alter their appearance. Treatment is a common, long-established practice; the important issue for a buyer is clear 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. Common in emerald; laboratories may describe the degree of clarity enhancement, so read the terminology used on that report. |
| 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 a specific stone. Its scope varies: it may include carat weight, millimetre dimensions, material identification, natural or laboratory-grown status and detectable treatments. Some reports include an opinion on geographic origin where that service is available. Read the fields actually provided and verify the report number with the issuing laboratory.
What a certificate does not do is establish that wearing the stone will produce a health, wealth or other promised outcome. A material-identification report should not be presented as evidence for those claims.
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 terms that are not interchangeable: check the issuer, tested item and scope. At Divine Hindu, any certification claim must be checked against the specific product listing and report. A report mentioned for a Karungali (Ebony) product should not be read as certification of a gemstone. Gemmological documentation, where available for the chosen stone, should be checked for its stated scope: species, natural or synthetic, weight, dimensions and detectable 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 4.6 carats.
The trap to avoid is the kacchi or goldsmith's ratti of about 121.5 mg, which is one-third 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 Weight Guide.
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 Weight Guide →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. Compare verified material and condition within your budget; neither a particular size nor a quality label guarantees resale value.
- 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?
A practical rule of thumb used by some practitioners 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, or about 4.6 to 5.5 carats using the conversion in this guide. It is not a universal requirement or proof of an outcome. Ask the adviser for the basis of the recommendation, and compare the actual material, treatment, condition and price rather than weight alone.
Is the body-weight formula for gemstone weight found in the shastras?
Do not assume a body-weight formula is a universal scriptural requirement. Traditional discussions of gems address qualities, flaws and graha associations, but an exact prescription should be supported by a named text, edition and verse if it is presented as scriptural. Ask the adviser to distinguish that citation from a trade custom or personal recommendation.
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. The label alone does not establish a standardized laboratory grade; ask the seller to state the criteria and supporting report. 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. Check the relevant features through examination and the actual scope of a laboratory report; eye-clean appearance is assessed without magnification. Ask for the specifics rather than accepting the label.
Are treated gemstones acceptable?
Many coloured gemstones are treated to alter their appearance. Treatment is common and long-established, and clear disclosure is essential. 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?
The scope of a gem laboratory report varies. It may include carat weight, millimetre dimensions, material identification, natural or laboratory-grown status and detectable treatments; some reports also include an opinion on geographic origin. Read the fields actually provided and verify the report number with the issuing laboratory. Such a report does not establish a health, wealth or other outcome from wearing the stone.
Is a gem lab certificate the same as government certification?
The terms are not interchangeable: check the issuer, tested item and scope. A gemstone laboratory may itself be governmental; what matters is the actual report. At Divine Hindu, check the specific listing and report for any certification claim. A report for Karungali (Ebony) does not certify a different gemstone. If a seller describes a coloured stone as government certified, ask which document they mean, who issued it and what it states.
