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White, cream, pink, gray, black

Pearl birthstone

Pearl, the birthstone for June, is calcium carbonate (aragonite) in a matrix of conchiolin, white, cream, pink, gray, black, rated 2.5–4.5 on the Mohs scale. Traditionally, it is associated with sincerity, emotional maturity and quiet dignity — attributed, not demonstrated.

Mohs hardness
2.5–4.5 window glass scratches it
Crystal system
Orthorhombic (aragonite)
Pliny, AD 77
Book 9.54 as “margarita”
Main sources today
Japan also China, Australia

Pliny, Natural History, tr. Bostock and Riley.

Stones described in similar terms: turquoise, malachite, amber, selenite and aquamarine.

Listed under: June birthstone and Gemini birthstones.

Linked in crystal practice with the sacral chakra and crown chakra.

Further along the same lines: diamond, rose quartz and ruby.

Pearl Birthstone: The June Stone — Meaning and Properties

Is Pearl a birthstone?

Yes. Pearl is the modern birthstone for June.

By zodiac sign it belongs to Gemini.

Properties

Composition Calcium carbonate (aragonite) in a matrix of conchiolin
Hardness (Mohs) 2.5–4.5
Crystal system Orthorhombic (aragonite)
Color White, cream, pink, gray, black
Main sources Japan, China, Australia, French Polynesia, Philippines

Worth knowing

Soft enough to scratch with a fingernail and dissolved by acid — perfume, vinegar and sweat all damage it.

History

One of the few gems made by a living animal — coral is another; harvested since at least 2300 BCE in China.

Buying

Buying Pearl: fakes, value and treatments

What it is confused with

Coated glass and plastic beads. Rubbed gently against the front teeth, real pearls feel slightly gritty while imitations feel smooth.

What decides the price

Luster, surface, shape, size and nacre thickness. Natural pearls are extremely rare; almost all pearls sold today are cultured, freshwater being cheaper than Akoya, Tahitian and South Sea.

Where it is used

Strands, studs and drops; pearls are also the traditional thirtieth anniversary gift.

A less familiar fact

Kokichi Mikimoto grew his first cultured pearl — a hemispherical blister pearl — in Japan in 1893; the round cultured pearls that transformed the market came from the Mise–Nishikawa method in the following decades.

Practical

Caring for Pearl

How to clean it

Wipe with a damp cloth after wearing. Put pearls on last, after perfume and hairspray, and never soak them.

How to tell it is real

The tooth test still works: rub the pearl gently against a tooth edge. Real nacre feels gritty; plastic and glass feel glassy-smooth.

How to store stones so they do not scratch each other →

How hard is Pearl?

Pearl nacre is soft calcium carbonate, so grit scuffs it and acids etch it; a strand ages through dull, scratched nacre rather than breakage, and a ring wears it down fastest. Among the stones in this reference, the next softer is Lepidolite (2.5–3) and the next harder Malachite (3.5–4).

Pearl on the Mohs hardness scale
Pearl on the Mohs hardness scaleMohs scale from talc (1) to diamond (10), with the 43 stones of our reference as dots and Pearl (2.5–4.5) marked as a bar.Pearl: Mohs 2.5–4.5Pearl 2.5–4.5Garnet: Mohs 6.5–7.5Amethyst: Mohs 7Citrine: Mohs 7Rose Quartz: Mohs 7Clear Quartz: Mohs 7Smoky Quartz: Mohs 7Aquamarine: Mohs 7.5–8Emerald: Mohs 7.5–8Bloodstone: Mohs 6.5–7Peridot: Mohs 6.5–7Sardonyx: Mohs 6.5–7Zircon: Mohs 6–7.5Carnelian: Mohs 6.5–7Onyx: Mohs 6.5–7Agate: Mohs 6.5–7Tiger's Eye: Mohs 6.5–7Aventurine: Mohs 6.5–7Diamond: Mohs 10Pearl: Mohs 2.5–4.5Alexandrite: Mohs 8.5Moonstone: Mohs 6–6.5Labradorite: Mohs 6–6.5Pyrite: Mohs 6–6.5Ruby: Mohs 9Sapphire: Mohs 9Spinel: Mohs 8Topaz: Mohs 8Opal: Mohs 5.5–6.5Rhodonite: Mohs 5.5–6.5Tourmaline: Mohs 7–7.5Turquoise: Mohs 5–6Lapis Lazuli: Mohs 5–6Hematite: Mohs 5–6Tanzanite: Mohs 6–7Jade: Mohs 6–7Obsidian: Mohs 5–5.5Malachite: Mohs 3.5–4Amber: Mohs 2–2.5Selenite: Mohs 2Fluorite: Mohs 4Sodalite: Mohs 5.5–6Kyanite: Mohs 4.5–7Lepidolite: Mohs 2.5–31Talc2Gypsum3Calcite4Fluorite5Apatite6Orthoclase7Quartz8Topaz9Corundum10Diamondfingernail 2.5window glass 5.5household dust (quartz) 7Source: Mohs scale minerals · ranges from our 43-stone referenceastrohot.com
Pearl on the Mohs hardness scaleMohs scale from talc (1) to diamond (10), with the 43 stones of our reference as dots and Pearl (2.5–4.5) marked as a bar.Pearl: Mohs 2.5–4.5Pearl 2.5–4.51Talc2Gypsum3Calcite4Fluorite5Apatite6Orthoclase7Quartz8Topaz9Corundum10Diamondfingernail 2.5glass 5.5dust 7Source: Mohs scale minerals · ranges from our 43-stone referenceastrohot.com

Pearl, at 2.5–4.5, is harder than 3 of the other 42 stones here and softer than 39.

Primary source

What Pliny the Elder wrote about Pearl

Pliny on margarita
“The first rank then, and the very highest position among all valuables, belongs to the pearl.”
Pliny the Elder, The Natural History, translated by John Bostock and H. T. Riley (London: H. G. Bohn, 1855–57), book 9, chapter 54 — read the original text. Pliny gives pearls several chapters, including the story of Cleopatra dissolving one in vinegar to win a wager with Mark Antony. Who Pliny was and why we quote him →

Traditional associations

Pearl is traditionally associated with sincerity, emotional maturity and quiet dignity. Chakra in crystal practice: Sacral, Crown. Element: Water.

What is measured here and what is tradition →

Questions about Pearl

What is Pearl made of?

Calcium carbonate (aragonite) in a matrix of conchiolin, crystallizing in the orthorhombic (aragonite) system.

Which month is Pearl the birthstone for?

June.

Where does Pearl come from?

Japan, China, Australia, French Polynesia, Philippines.

Can Pearl be worn every day?

Not in a ring. At 2.5–4.5 on the Mohs scale it is better kept for pendants, earrings or display, away from perfume, hairspray and sweat, which etch the nacre.

← All gemstones

Sources

  1. Pliny the Elder, The Natural History, translated by John Bostock and H. T. Riley (London: H. G. Bohn, 1855–57), book 9, chapter 54

Statements of fact on this page were checked against these sources in October 2026. How we choose and check sources: editorial policy.

Cite this page

AstroHot. “Pearl Birthstone: The June Stone — Meaning and Properties.” Accessed October 28, 2026. https://astrohot.com/crystals/gemstones/pearl/

For Wikipedia {{cite web |title=Pearl Birthstone: The June Stone — Meaning and Properties |url=https://astrohot.com/crystals/gemstones/pearl/ |website=AstroHot |access-date=2026-10-28}}