Coral

Add one script tag to your page:

<div data-gemfyi="entity" data-slug="coral"></div>
<script src="https://cdn.jsdelivr.net/npm/gemfyi-embed@1/dist/embed.min.js" defer></script>

Embed as an iframe:

<iframe src="https://gemfyi.com/iframe/entity/coral/?style=modern&theme=light" width="420" height="400" frameborder="0" loading="lazy" style="border:0;border-radius:10px;max-width:100%"></iframe>

Paste the URL in WordPress, Medium, or Ghost:

https://gemfyi.com/gems/coral/

Shields.io-compatible SVG badge:

Coral badge ![Coral](https://gemfyi.com/badge/entity/coral.svg)

Web Component:

<gemfyi-entity slug="coral"></gemfyi-entity>
<script src="https://cdn.jsdelivr.net/npm/gemfyi-embed@1/dist/embed.min.js" defer></script>

Physical & Optical Properties

Category Organic Gems
Mohs Hardness 3.0 – 4.0
Specific Gravity 2.6 – 2.7
Refractive Index 1.486 – 1.658
Crystal System Trigonal
Cleavage None
Color various
Birefringence 0.16
Pleochroism Absent

Mohs Hardness

Mohs Hardness: 3.0 – 4.0
1 Soft10 Hard

Crystal System

a a a Trigonal (Rhombohedral) a = b = c, α = β = γ ≠ 90°

Value & Market

Price Tier Budget (< $50/ct)

Where to Buy Coral

Amazon Wide selection

Links may earn a commission at no extra cost to you.

Treatments

Dyed: mostly with polymer treatment, color and resin concentration in fractures, cavities and branches junctions. Hot point test (acetone test in some cases) may reveal the treatment. Dyed pink to red from white variety: color dignostic if from "bamboo" type (natural color is white to brownish). Dyed blue from grayish: commonly with resin treatment: light blue color concentration in pits and cracks - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 9 Artificial pressed product (ceramics) consisting of calcite - Red; opaque; RI 1.486 - 1.658; Birefringence 0.172; Uniaxial/-; SG 2.60 - 2.70; Hardness 3.5 - 4; Trigonal. - Gemmological Tables, Ulrich Henn and Claudio C. Milisenda, 2004, p 3 3 to 4Walter Schumann, Gemstones of the world (2001) More from other references 2.60 to 2.70Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) BrittleWalter Schumann, Gemstones of the world (2001) NoneWalter Schumann, Gemstones of the world (2001) Irregular,SplinteryWalter Schumann, Gemstones of the world (2001) 1.486 to 1.658Walter Schumann, Gemstones of the world (2001) White and redMore from other references Uniaxial/-Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) 0.160 to 0.172Walter Schumann, Gemstones of the world (2001) White and redMore from other references AbsentWalter Schumann, Gemstones of the world (2001) NoneWalter Schumann, Gemstones of the world (2001) Red, pink, white, orange, blue, brownUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) Translucent,OpaqueWalter Schumann, Gemstones of the world (2001) More from other references Dull purplish-redHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) TrigonalUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) Distinctive wavy parallel fibrous structureHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) Coral information at mindat.org

About Coral

Precious coral is the hard, calcium carbonate skeleton secreted by marine polyps of the order Gorgonacea, carved into beads, cameos, and figurines since ancient times. The most prized variety—'ox-blood' or 'Moro' coral from the Mediterranean and Japanese seas—displays a deep, saturated red color that has been treasured in Chinese, Tibetan, Italian, and Native American cultures for centuries. Due to overharvesting and marine habitat loss, many coral species are now protected, making precious coral increasingly rare and regulated.

Compare With

Coral vs Pearl

Jewelry Use

Durability 2/10

Science FYI Family

ChemFYI chemfyi.com AlloyFYI alloyfyi.com GemFYI gemfyi.com StarFYI starfyi.com MineralFYI mineralfyi.com

Frequently Asked Questions

What is Coral?
Precious coral is the hard, calcium carbonate skeleton secreted by marine polyps of the order Gorgonacea, carved into beads, cameos, and figurines since ancient times. The most prized variety—'ox-blood' or 'Moro' coral from the Mediterranean and Japanese seas—displays a deep, saturated red color tha
What is the hardness of Coral?
Coral has a Mohs hardness of 3.0 to 4.0, making it relatively soft for use in jewelry.
What color is Coral?
Coral is primarily Various.
How much does Coral cost?
Coral falls into the Budget (< $50/ct) price range. Prices vary based on color, clarity, cut, and origin.
What is the crystal system of Coral?
Coral belongs to the Trigonal crystal system.

More Organic Gems Gems

Amber
Pearl