The Complete Guide To
Ruby
Manik. Mohs 9. The same mineral as sapphire, turned red by chromium — and the rarest of the great corundum colours in large, clean sizes.
At a glance
Ruby
A corundum, chemically the same mineral as sapphire. Chromium gives it both its red and the fluorescence that makes fine ruby glow in sunlight.
- Mohs 9
- July birthstone
- Sun / Surya
- Everyday wear
- Hardness (Mohs)
- 9
- Family
- Corundum
- Colour range
- Pinkish red to vivid red to deep purplish red
- Key origins
- Burma, Mozambique, Thailand, Madagascar, Sri Lanka
- Planet
- Sun (Surya)
- Birth month
- July
- Common treatment
- Heat (always disclosed)
- Daily wear
- Excellent
- Also known as
- Manik, Manikya
- Refractive index
- 1.762 – 1.770
Chapter 01 · Overview
The red half of the hardest gemstone family
Ruby is corundum — the same mineral as sapphire, coloured red by traces of chromium rather than iron and titanium. Only red corundum is called ruby. Everything else in the family is a sapphire, named by its colour.
That shared chemistry puts ruby at 9 on the Mohs scale, which makes it one of the very few coloured stones you can wear in a ring every day without thinking about it. Chromium does something else as well: it causes fluorescence, so a fine ruby appears to light up from within in daylight. It is the reason two stones of the same measured colour can look completely different on the hand.
- Mohs 9 — genuinely suited to an everyday ring
- Colour ranges from pinkish red through vivid red to deep purplish red
- Chromium fluorescence makes fine ruby glow in sunlight
- The rarest of the big corundum colours in large, clean sizes
- Both the July birthstone and the Sun's stone in Vedic astrology
One thing to know first: a great deal of what is sold as ruby is lead-glass filled composite material — heavily fractured low-grade corundum made to look transparent. It is worth a small fraction of the price of a real ruby. Chapter 03 explains how to tell the difference.
Chapter 02 · Quality
What separates a good ruby from a great one
Heat-treated vs Glass-filled Ruby
One is a real ruby that has been through an accepted process. The other is a composite that behaves nothing like a ruby.
Heat-treated Ruby
- The industry standard — most rubies sold are heated
- Heat improves colour and dissolves silk permanently
- Stable and permanent, not a coating, dye or filler
- Still a real ruby, and priced as one
- Must always be disclosed on the certificate
Lead-glass Filled Ruby
- A composite — fractured low-grade corundum filled with lead glass
- Fragile, because the glass is holding the stone together
- Damaged by ordinary jewellers' heat during repairs or resizing
- Attacked by lemon juice and household acids
- Worth a small fraction of the price, and must be disclosed
Origin matters too. Burmese (Mogok) rubies are the historic benchmark for colour and fluorescence, while Mozambique is now the largest source of fine material and offers the best combination of quality and availability. Thailand, Madagascar and Sri Lanka supply the rest of the market. Origin claims need lab backing — ask for both origin and treatment in writing.
Chapter 04 · Shapes & Cuts
Which cut suits you
Cut affects price per carat as much as it affects looks. Here is what each one gives you.
Oval
The most common ruby cut. It follows the natural shape of the rough, so less weight is lost and you pay less per carat. Elongating on the finger.
Cushion
A soft square with rounded corners. Holds red deeply in the centre and reads slightly larger than an oval of the same weight. The classic antique look.
Round
The most brilliant cut, and the most wasteful of rough — expect a premium per carat, which bites harder on ruby than on any other corundum. Best on smaller, richly saturated stones.
Emerald
A step cut with long, clean facets. Shows colour as broad flashes rather than sparkle, so it demands good clarity and even saturation. Uncommon in ruby, and quietly modern.
Pear
A teardrop that flatters the hand and works as well in a pendant as a ring. Watch the point — it needs a protective setting.
Cabochon
Polished rather than faceted. Used for stones with heavy silk, and the only cut that can show a star (asterism). Traditional for astrological wear.
Chapter 05 · Astrology
Ruby and the Sun
The traditional Vedic profile for Manik — when, how and who it is worn by.
Sun (Surya)
Planet of authority, vitality, confidence & recognition
Ruby (Manik)
- Planet
- Sun
- Day to wear
- Sunday
- Time
- Sunrise
- Metal
- Gold or Copper
- Finger
- Ring Finger
- Colour
- Red
- Mantra
- Om Hraam Hreem Hraum Sah Suryaya Namah
- Minimum weight
- 3 Ratti
Traditionally worn by
- Leadership
- Government
- Medicine
- Public Life
- Confidence
- Vitality
Varniya Note
Ruby is traditionally associated with the Sun and worn on a Sunday at sunrise, set in gold so the stone touches the skin. Astrological gemstone selection is a matter of personal belief and tradition rather than demonstrated effect — please consult a qualified astrologer before choosing a stone for astrological purposes.
Why Ruby?
- Traditionally worn for confidence, authority and vitality
- Mohs 9 — outstanding durability for daily wear
- Vivid red with chromium fluorescence is among the most prized colours in jewellery
- Natural, certified and glass-free stones are traditionally preferred for astrological use
- Set in gold so the stone touches the skin, as tradition requires
Chapter 06 · Ratti & Carat
Ratti to carat, and how much to wear
Ratti is the traditional Indian unit still used for gemstones. One Ratti is approximately 0.91 carat, or 0.182 grams. Note that fine ruby above 5 Ratti is genuinely rare, so the price band climbs hard rather than evenly.
| 3 Ratti | 5 Ratti | 7 Ratti | 9 Ratti | 11 Ratti | |
|---|---|---|---|---|---|
| Carat (approx) | 2.73 ct | 4.55 ct | 6.37 ct | 8.19 ct | 10.01 ct |
| Weight in grams | 0.55 g | 0.91 g | 1.27 g | 1.64 g | 2.00 g |
| Why this weight | Minimum for astrological wear | Most common first choice | Standard astrological weight, already scarce in fine colour | Rare in fine quality, usually made to order | Exceptionally rare in fine colour |
| Price band | |||||
| Commonly set as | Slim fingers, pendants | Everyday rings | Statement rings | Statement rings | Collector pieces |
Swipe to see more weights
Chapter 07 · How to Buy
Six things to check before you pay
Coloured gemstones have no universal grading scale, which means the seller's word and the certificate are doing most of the work. With ruby there is one check that matters more than all the others: whether the stone has been filled with lead glass.
- Ask in writing whether the stone is lead-glass filled or a composite — before anything else
- Get a certificate from an independent lab — IGI, GIA or GRS, not an in-house one
- Confirm the treatment on paper: heat only, or heat with residue, or filled
- Check the stone in daylight and again under warm indoor light
- Tilt it to look for windowing and dead dark zones
- Make sure the return window is long enough to get a second opinion
Lead-glass filled ruby, plainly: heavily fractured low-grade material is filled with molten lead glass so the fractures disappear and the stone looks transparent. It is very common in the market. It is worth a small fraction of the price of a real ruby, it is damaged by the ordinary heat a jeweller uses for repairs and resizing, and it is attacked by lemon juice and household acids. It must be disclosed. If a ruby looks far too good for its price, this is usually why.
Chapter 08 · Alternatives
Ruby and its alternatives
If ruby is not the right fit on budget or durability, these are the honest comparisons.
| Ruby | Lab Ruby | Red Spinel | Rubellite Tourmaline | Garnet | Pink Sapphire | |
|---|---|---|---|---|---|---|
| Hardness (Mohs) | 9 | 9 | 8 | 7–7.5 | 7–7.5 | 9 |
| Brilliance | ||||||
| Colour | Pigeon's blood to deep red | Consistent vivid red | Bright red to hot pink-red | Raspberry to purplish red | Deep red to brownish red | Pink to pinkish red |
| Daily Wear | Excellent | Excellent | Excellent | Good | Good | Excellent |
| Budget | ||||||
| Best For | A lifetime everyday stone | Same look, far less cost | Collectors, usually untreated | Larger stones on a smaller budget | Accessible everyday red | A softer alternative to ruby |
Swipe to compare more
Chapter 09 · Care
Looking after a Ruby
Hard enough for anything — with one important exception if the stone has been filled.
-
1
Wear it freely
At Mohs 9, a natural ruby is one of the few coloured stones you genuinely do not need to baby. Daily rings are fine.
-
2
Clean it simply
Warm water, a drop of mild dish soap and a soft toothbrush. Rinse and pat dry. Never use lemon juice, vinegar or any acidic cleaner — acids attack lead glass and can etch a filled stone permanently.
-
3
Keep filled stones out of the ultrasonic
Ultrasonic and steam cleaners are safe for untreated and heated rubies, but not for glass-filled or fracture-filled ones. If you are not certain which you own, clean by hand.
-
4
Tell your jeweller before any repair
The torch used for ordinary sizing and prong work will damage a glass-filled ruby. Say so before the piece goes on the bench, and ask that the stone be removed first if there is any doubt.
-
5
Check the prongs yearly
Bring it in once a year so we can check the setting, re-tighten the prongs and re-polish the metal. This is what actually loses stones, not the stone itself.
Ready when you are
Shop Ruby
Every stone certified, every treatment disclosed.
Chapter 10 · Questions
Ruby FAQs
Is Ruby good for an engagement ring?
Yes — it is one of the best coloured stones for the job. At Mohs 9 it stands up to daily wear far better than emerald or tanzanite. The one condition is that it must be a natural or lab grown ruby, not a lead-glass filled composite, which is too fragile for a ring worn every day.
What is a glass-filled ruby, and how do I avoid one?
It is heavily fractured low-grade corundum whose fractures have been filled with molten lead glass so the stone looks transparent. It is common, it is worth a small fraction of the price of a real ruby, and it is damaged by ordinary jewellers' heat and by acids such as lemon juice. Avoid it by buying only with an independent lab report that states the treatment, and by asking the seller in writing whether the stone is filled or a composite.
What does pigeon's blood mean?
It is the trade term for the most prized ruby colour — a vivid, pure red with a slight blue undertone and strong fluorescence. It is a descriptive term rather than a measured grade, so it means most when it appears on a report from a lab such as GRS or GIA rather than in a seller's description.
Is Burmese ruby better than Mozambican?
Burma — Mogok in particular — is the historic benchmark and still commands the highest prices for comparable quality. Mozambique is now the largest source of fine ruby and produces excellent material, often at better value. Judge the stone in front of you first, and treat any origin claim as meaningful only when a laboratory has backed it.
How much does Ruby cost per carat?
The range is enormous — from a few thousand rupees per carat for filled or heavily included commercial material to several lakhs per carat for fine unheated Burmese stones. Colour is the single biggest factor, and price per carat climbs very steeply above 2 carats and far more steeply above 5. We will always show you the reasoning behind a price.
Are lab grown rubies real rubies?
Yes. Lab grown ruby is chemically and optically identical to mined ruby — the difference is origin, not authenticity. It costs a fraction of the price and looks the same. It is not traditionally used for astrological purposes.
How many ratti of Ruby should I wear, and on which finger?
Traditionally 3 Ratti is considered the minimum for astrological wear, with 5 Ratti being the most common choice. In Vedic tradition Ruby is worn on the ring finger of the working hand, set in gold or copper, on a Sunday at sunrise, with the stone touching the skin. The right weight depends on your chart and should be confirmed by a qualified astrologer.
Still deciding?
We'll shortlist stones for you
Tell us your budget, your setting and whether you are buying for beauty or for the Sun. We'll send you three options with the reasoning behind each.
