Ruby, or manik
Manik is worn for the Sun in Jyotish. As a mineral it is red corundum, and it is one of the most often treated and imitated gems. Here is what to check before you buy.
The short answer
Ruby (manik) is the gem of Surya, the Sun, in Jyotish. As a mineral it is red corundum, aluminium oxide coloured by chromium, with a hardness of 9. Most rubies on sale are heated, a common and accepted treatment if disclosed. Some cheap “rubies” are low-grade corundum filled with lead glass, which a laboratory calls a composite, and synthetic rubies have been made for over a century. Ask for a report that states natural corundum, the treatment and the weight in carats.
In this guide
What ruby is
Ruby is the red variety of corundum, the same mineral as sapphire. Chromium gives it its colour, and the finest stones glow red even in daylight. It is hard (9 on the Mohs scale, second only to diamond among the Navaratna) and tough, so it wears well. Important sources include Mogok in Myanmar, Mozambique (the largest source since about 2009), Thailand and Cambodia, Sri Lanka, Madagascar, Tanzania and Afghanistan. India produces corundum, mostly opaque, and Jaipur is one of the world's great centres for cutting coloured stones.
| Mineral | Corundum (aluminium oxide), red from chromium |
|---|---|
| Hardness | 9 |
| Specific gravity | About 4.0 |
| Main sources | Myanmar, Mozambique, Thailand, Sri Lanka, Madagascar |
| Hindi and Sanskrit | Manik, manikya |
Ruby (manik) in Jyotish
The manik sits at the centre of the Navaratna setting, for the Sun is the king of the grahas. Astrologers recommend it when the Sun is judged weak but well placed in the chart, for confidence, authority and vitality, and many warn against it when the Sun is badly placed or hostile to the person's ascendant.
- Graha: Surya, the Sun.
- Day to first wear it: Sunday, commonly in the morning.
- Finger and metal: the ring finger of the working hand, set in gold or copper.
- Substitutes (upratna): red garnet and red spinel are the usual lower-cost alternatives.
Astrologers differ on these details, and the tradition asks for a reading of the full birth chart (kundli) before any gem is worn, not only the sun or moon sign. Our guide to gemstones and zodiac signs explains why.
Ruby strengthens a weak Sun: leadership, status, confidence and health of the heart and eyes. It should be natural, clear and without flaws, which the classical texts list in detail, and worn only after a chart reading.
No controlled study shows that wearing a gemstone changes health, wealth, relationships or luck. The claim cannot be tested by a laboratory. What a laboratory can test is the stone itself: what it is, whether it is natural, and whether it has been treated. Those facts decide its price, and they are what you should insist on.
Treatments, synthetics and imitations
Heating to improve colour and clarity is routine for ruby; an unheated ruby of fine colour is rare and costs many times more. The treatments to worry about are the ones that hide what the stone is.
| What you might be sold | What it is | What a report says |
|---|---|---|
| Heated ruby | Natural ruby heated to improve colour; stable and widely accepted | “Natural corundum, ruby; indications of heating” |
| Lead-glass-filled “ruby” | Low-grade, cracked corundum filled with lead glass; can be damaged by heat and even lemon juice | “Composite ruby” or “manufactured product”, not natural ruby |
| Synthetic ruby | Laboratory-grown corundum, made since about 1900; same chemistry | “Synthetic corundum” |
| Garnet, red spinel or glass | A different material sold as ruby | Names the actual material |
Treatment is not dishonest when it is disclosed; undisclosed treatment is. Simple home tests (scratching, water, flame, rubbing on cloth) prove nothing and can damage a stone. See how to tell whether a gem is natural.
Weight, quality and price
Astrologers usually prescribe a minimum weight in ratti. Sellers convert ratti to carats differently, most often at about 0.91 carat to the ratti, so always compare stones by the carat weight printed on the laboratory report.
Price depends on colour above all (a strong, pure red is most valued), then clarity, size, treatment and origin claim. A “Burmese” or “unheated” claim adds a great deal, so it needs a report from a laboratory equipped to test for it. Very cheap, very red, very clean “rubies” are almost always composite or synthetic.
Wearing and care
Ruby is hard and tough and can be cleaned in warm soapy water with a soft brush. Do not clean a lead-glass-filled stone with ultrasonic cleaners, heat or acids, and have a jeweller check the setting once a year.
Buying ruby sensibly
- Get the recommendation in writing: gem, minimum weight, metal and finger.
- Ask for a laboratory report for this exact stone that names the species (natural corundum, ruby), states natural or synthetic, and discloses any treatment.
- Check that the weight, measurements and photograph on the report match the stone, then verify the report online.
- Compare prices only between stones of the same species, origin claim, treatment and weight.
- Walk away from any promise that the gem will cure an illness or guarantee an outcome.
Readers often ask where to buy. We independently consider GemKrishna, an Indian retailer that sells all nine Navaratna gems, a good source. Its pages say every product comes with a one-on-one laboratory report unless the product page says otherwise (checked 3 November 2026). AYU4 has no relationship with it of any kind. The same checks apply to any seller. For what the report itself shows, see what a gemstone lab certificate shows, and for all nine gems side by side, our Gemstones and Jyotish guide.
Where to buy
If you have decided to buy, choose a seller that gives authenticity you can check yourself: a lab or X-ray report you can verify online. Here are options we can point to; AYU4 takes no commission from any seller.
- GemKrishna: its ruby (manik) collection, with lab reports. A good starting point, which we independently consider a reliable source; AYU4 has no connection to it.
- Rudra Centre: its manik (ruby) stones. A Mumbai seller, established 1997, that publishes its address, lab certificates and return policy.
- Spiritual and crystal stores near you: fine for common stones, if they name the exact stone, disclose dyeing or heating and give a bill. See what to check.
Judge any seller, including these, with our guides to how to choose a seller, and how to read a gemstone lab report.
Questions readers ask
Manik ratna kaun pehne?
In Jyotish, manik (ruby) is the gem of the Sun and is linked with Simha (Leo). Astrologers choose it from the whole birth chart, not the sign alone, and differ on the same chart. No study shows it changes outcomes.
What is manik stone?
Manik is the Hindi name for ruby, red corundum, worn in Jyotish for the Sun.
Is a heated ruby natural?
Yes. Heating is a common treatment of natural ruby. The report should say “indications of heating”. A lead-glass-filled stone is different: it is a composite, not a natural ruby.
Which finger is ruby worn on?
Most astrologers advise the ring finger, in gold or copper, first worn on a Sunday morning. Practices vary.
How can I tell if my ruby is real?
Only a gem laboratory can tell reliably. Ask for a report that names natural corundum and discloses treatment, and verify it online.
What can I wear instead of ruby?
Astrologers often suggest red garnet or red spinel as substitutes (upratna).
Sources
- GIA Gem Encyclopedia: Ruby
- GIA: Lead glass-filled ruby, identification and terminology. Gems & Gemology and GIA laboratory research
- Mindat.org: Corundum
- Varahamihira, Brihat Samhita, chapters on gems (ratna pariksha), 6th century
- Garuda Purana, Purva Khanda, chapters on the examination of gems
- AYU4 guide: what a gemstone lab certificate shows
A note on health. This guide explains a tradition. It is not medical advice, and nothing in it is a treatment for any disease. See a qualified doctor for symptoms, and do not stop or change a prescribed medicine on the strength of anything you read here. Full medical disclaimer.
