The Complete Guide To
Pearl
Moti. Mohs 2.5 to 4.5. The one gem in this series grown by a living creature rather than the earth — and the one that asks the most of you in return.
At a glance
Pearl
An organic gem — layers of nacre laid down by a mollusc rather than crystallised underground. The softest stone in this series, and the one graded by an entirely different set of rules.
- Mohs 2.5 – 4.5
- June birthstone
- Moon / Chandra
- Gentle wear
- Hardness (Mohs)
- 2.5 – 4.5
- Family
- Organic — nacre, not a mineral
- Colour range
- White, cream, gold, grey, peacock
- Key origins
- Japan, China, Australia, French Polynesia
- Planet
- Moon (Chandra)
- Birth month
- June
- Common treatment
- Bleaching and polishing (routine)
- Daily wear
- Gentle wear only
- Also known as
- Moti, Mukta
- Measured in
- Millimetres, not carats
Chapter 01 · Overview
The odd one out, and proud of it
Every other gemstone in this series is a mineral that formed under heat and pressure. A pearl is not. It is nacre — microscopic platelets of aragonite bound together by a protein called conchiolin — laid down in layer after layer by a living mollusc around something it cannot expel. The soft sheen you are looking at is light bouncing off several thousand of those layers at once.
That organic origin sets the terms for everything else. Pearl sits at 2.5 to 4.5 on the Mohs scale, softer than a copper coin and far softer than the sapphire or emerald in the same jewellery box. It is sold by millimetre, not by carat. And the four Cs you may have learned for diamonds do not apply to it at all.
- Not a mineral — nacre, laid down in layers by a living mollusc
- Mohs 2.5 to 4.5, by some distance the softest stone in this series
- Judged on lustre, surface, nacre thickness and shape, not the four Cs
- Sized by diameter in millimetres rather than by weight in carats
- The June birthstone, and the traditional third and thirtieth anniversary gift
One thing to know first: natural, wild pearls are effectively an auction and collector category — a handful reach the market each year and they are priced accordingly. Essentially every pearl sold today, including every fine one, is cultured. That is not a compromise and it is not an imitation; it is simply how pearls are produced now, and any honest seller will tell you so without being asked.
Chapter 02 · Quality
The four things that actually decide a pearl
Freshwater vs Saltwater Pearls
Both are cultured, and both are real pearls. They are grown by different animals, in different water, by different methods.
Freshwater Pearls
- Grown in mussels, mostly in the lakes and rivers of China
- Usually solid nacre, with no bead at the centre
- The widest range of shapes, sizes and natural colours
- Excellent value — several pearls per mussel, so supply is good
- Lustre is typically softer and warmer than saltwater
Saltwater Pearls
- Grown in oysters — Akoya, South Sea and Tahitian
- Bead-nucleated, so nacre thickness has to be checked and stated
- Rounder on average, with a sharper, more mirror-like lustre
- One pearl per oyster, which is why the prices are far higher
- Graded and sold with nacre thickness as a named factor
The four types worth knowing. Akoya — Japan and China, 2 to 10mm, the sharpest lustre and the classic white round. South Sea — Australia, the Philippines and Indonesia, 8 to 20mm, white or golden, the thickest nacre and the highest prices. Tahitian — French Polynesia, 8 to 16mm, naturally dark grey through to peacock green. Freshwater — China, 2 to 15mm, the most affordable and now genuinely excellent in quality. Bleaching and light polishing are routine across all four and are not usually itemised. Dyeing and irradiation do happen, particularly with coloured freshwater and so-called chocolate pearls, and those must be disclosed to you.
Chapter 04 · Shapes
Which shape suits you
Shape moves the price as much as it moves the look. Here is what each one gives you.
Round
The rarest shape and the benchmark for value. A true round should not wobble when rolled across a flat surface. Expect a significant premium, particularly above 8mm.
Near-Round
Very slightly off true — a difference that all but disappears once the pearl is strung or set. Often a third less than round, for a look most people cannot tell apart.
Oval
Longer than it is wide. Reads as deliberate in a drop earring or pendant, and gives you visible size for noticeably less than a round of the same length.
Drop
A teardrop tapering to one end. The most sought-after of the non-round shapes, especially as a matched pair for earrings, where symmetry between the two carries a premium.
Button
Round from the front, flattened from the side. Sits close and low, which makes it the practical choice for studs and for rings that need to clear a cuff.
Baroque
Irregular, and no two alike. Once treated as a by-product, now collected in its own right — frequently with outstanding lustre, and far more size for the money.
Chapter 05 · Astrology
Pearl and the Moon
The traditional Vedic profile for Moti — when, how and who it is worn by.
Moon (Chandra)
Planet of the mind, emotion, intuition & calm
Pearl (Moti)
- Planet
- Moon
- Day to wear
- Monday
- Time
- Evening
- Metal
- Silver
- Finger
- Little Finger
- Colour
- White
- Mantra
- Om Shraam Shreem Shraum Sah Chandraya Namah
- Minimum weight
- 3 Ratti
Traditionally worn by
- Emotional Balance
- Creative Work
- Caregiving
- Sleep
- Intuition
- Peace of Mind
Varniya Note
Loose astrological pearls are still weighed in ratti, even though jewellery pearls are sold by millimetre — ask a seller for both figures so you can compare like with like. Astrological gemstone selection is a personal belief — please consult a qualified astrologer before choosing a stone for astrological purposes.
Why Pearl?
- Traditionally worn for calm, emotional steadiness and clear thinking
- Natural or untreated pearls are traditionally preferred for astrological wear
- Set in silver, on the little finger, so the pearl touches the skin
- Undrilled pearls are preferred where available, as drilling weakens them
- Soft at Mohs 2.5 to 4.5, so an astrological ring needs a protective setting
Chapter 06 · Ratti & Millimetre
Ratti, carat and millimetre
Jewellery pearls are sold by diameter in millimetres. Astrological pearls are still weighed in ratti, so both figures are worth having. One Ratti is approximately 0.91 carat, or 0.182 grams — the diameters below are for a round pearl of typical density.
| 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 |
| Approx. diameter (round) | 6 – 7 mm | Around 8 mm | Around 9 mm | Around 10 mm | Around 11 mm |
| Why this weight | Minimum for astrological wear | Most common first choice | Standard astrological weight | Larger hands, bold settings | Rare in fine quality |
| Price band | |||||
| Commonly set as | Everyday rings, pendants | Rings and studs | Statement rings | Statement rings | Collector pieces |
Swipe to see more weights
Chapter 07 · How to Buy
Six things to check before you pay
Pearls have no independent grading scale. The A to AAA and Hanadama-style labels you will see are set by each seller or each farm, not by a neutral lab, so a letter on a tag means only what that seller decided it means. What protects you is knowing where to look and what to ask.
- Judge lustre by a window in daylight, not under a shop spotlight
- Ask whether the pearl is freshwater or saltwater, and which type
- For bead-nucleated pearls, ask for the nacre thickness in millimetres
- Ask what has been done to it — bleaching and polishing are routine, dyeing and irradiation are not
- On a strand, check that the pearls match each other in colour, size and lustre
- Make sure the return window is long enough to see them in your own light
Red flags: a grading letter with no explanation of what it covers, a refusal to say whether a pearl has been dyed, and a chalky or blueish cast that usually means thin nacre. Coloured freshwater pearls and so-called "chocolate" pearls are frequently dyed or irradiated, and that has to be disclosed. A simple check: run a pearl gently along the edge of a tooth — nacre feels faintly gritty, while glass and plastic feel completely smooth.
Chapter 08 · Alternatives
Pearl and its alternatives
If a pearl is not the right fit on budget or durability, these are the honest comparisons. Shell pearl is man-made — ground shell coated in a pearlescent finish — and should always be sold as such.
| Pearl | Moonstone | Opal | White Sapphire | Mother of Pearl | Shell Pearl | |
|---|---|---|---|---|---|---|
| Hardness (Mohs) | 2.5 – 4.5 | 6 – 6.5 | 5.5 – 6.5 | 9 | 2.5 – 4.5 | 3 – 4 |
| Lustre | ||||||
| Colour | White, cream, gold, grey | White with a blue sheen | Milky white with play of colour | Colourless to near-white | Iridescent white to grey | Very uniform white or cream |
| Daily Wear | Gentle wear | Moderate | Careful wear | Excellent | Gentle wear | Gentle wear |
| Budget | ||||||
| Best For | A lifetime piece, given care | A soft glow on a small budget | Colour and movement, occasion wear | A white stone built for daily wear | Inlay and larger flat surfaces | Matched look at the lowest cost |
Swipe to compare more
Chapter 09 · Care
Looking after a Pearl
This is the chapter that matters most. Pearls are the one gem here where care decides how long the piece lasts — five habits, and it will outlast you.
-
1
Last thing on, first thing off
Put pearls on after perfume, hairspray, sunscreen and make-up have gone on and dried, and take them off before anything else comes off. The alcohols and acids in cosmetics dissolve nacre, and so, slowly, does perspiration.
-
2
Wipe them after every wear
A soft cloth, barely damp with plain water, over each pearl before they go away, then dry with a second soft cloth. This single habit does more for a strand than everything else on this list combined.
-
3
Never ultrasonic, never steam
No ultrasonic cleaner, no steam cleaner, no jewellery dip, no detergent, no vinegar, no toothpaste. Each of these strips or etches the nacre, and that damage cannot be undone.
-
4
Store them flat, and let them breathe
Lay pearls flat in a soft pouch or a lined tray, away from harder stones that will scratch them. Never seal them in an airtight box or a plastic bag — nacre needs a little humidity, and without it it dries and crazes.
-
5
Restring on silk every year or two
A regularly worn strand should be restrung on silk with a knot between each pearl. The knots stop the pearls rubbing against one another, and mean that if the thread ever gives way you lose one pearl rather than all of them.
Ready when you are
Shop Pearl
Type, nacre and any treatment stated on every piece.
Chapter 10 · Questions
Pearl FAQs
Are cultured pearls real pearls?
Yes. A cultured pearl is grown by a living mollusc, from the same nacre, in the same way as a natural one — the only difference is that a technician placed the irritant rather than chance. Natural wild pearls are so rare that they are now essentially an auction category, so almost everything on the market, at every price, is cultured. Imitation pearls, which are glass or plastic with a coating, are a different thing entirely and must be described as such.
How can I tell a real pearl from an imitation?
Run it gently along the edge of a tooth: nacre feels faintly gritty, imitation feels perfectly smooth. Real pearls are usually cool to the touch at first and heavier than they look, and no two on a strand are identical. Around the drill hole, a real pearl shows a clean edge, while an imitation often shows a coating that has begun to flake.
Freshwater or saltwater — which should I buy?
It depends on what you want from the pearl. Freshwater gives you the best value, the widest choice of shape and colour, and usually solid nacre with no bead inside. Saltwater — Akoya, South Sea and Tahitian — gives you a rounder pearl with sharper, more mirror-like lustre, at several times the price. A good freshwater pearl beats a mediocre Akoya every time.
How much does a pearl cost?
The range is very wide. A small freshwater pearl can cost a few hundred rupees, while a matched strand of fine South Sea pearls runs into lakhs. Lustre moves the price more than anything else, followed by size in millimetres, surface cleanliness, roundness and type. We will always show you the reasoning behind a price.
How many ratti of Pearl should I wear?
Traditionally 3 Ratti is considered the minimum for astrological wear, with 5 to 7 Ratti the most common. Because pearls are usually quoted in millimetres, it is worth asking for both numbers — roughly, 3 Ratti is a 6 to 7mm round pearl and 7 Ratti is around 9mm. The right weight depends on your chart and should be confirmed by a qualified astrologer.
Can I wear pearls every day?
You can, but they need looking after in a way that a sapphire does not. At Mohs 2.5 to 4.5 nacre scratches easily and is attacked by cosmetics, perfume and perspiration. Earrings and pendants cope with daily wear well; a pearl ring takes far more punishment and is better kept for occasions, or set with the pearl protected.
Which finger should Pearl be worn on?
In Vedic tradition, Pearl is worn on the little finger of the working hand, set in silver, on a Monday evening. The stone should be set so that it touches the skin. An undrilled pearl is preferred where one can be found, since drilling weakens it.
Still deciding?
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Tell us your budget, the piece you have in mind, and whether you are buying for beauty or for the Moon. We'll send you three options with the reasoning behind each.
