Guide

Black Colored Gemstones: Which Black Stone Lasts in a Ring

Three kinds of black, the stones that survive daily wear, and the blacks that come from a dye bath.

By Ilyes MakriaUpdated Oct 28, 20264 min read

The short answer

For a black stone in a ring you wear every day, choose black sapphire, black spinel or black diamond. Tourmaline, jade and onyx hold up with care. Keep opal, obsidian, hematite, pearl and jet for earrings and pendants. Then ask one question: is the black natural? Black onyx almost never is.

Black stones for a ring at a glance
Black stone	Hardness (Mohs)	Everyday ring?
Black diamond	10	Yes, in a protective setting
Black sapphire	9	Yes
Black spinel	8	Yes
Black tourmaline, jade	6 to 7.5	Yes, with care
Onyx	6.5 to 7	Tough, scratches over time
Opal, hematite, obsidian, pearl, jet	2.5 to 6.5	Earrings and pendants

Which Gemstones Are Black?

Black means three different things in a stone, and each changes what you are looking at.

Black all the way through. Onyx, jet, obsidian and hematite let little or no light through: what you see is the surface.
So dark it reads black. Some stones that are normally transparent grow so dark they look black. Hold one to a strong light and the color comes through.
Black as a background. In black opal, a dark body sets off flashes of color.

Ten black gemstones, one picture each

Grouped by kind of black. The last line says whether it suits a ring worn every day.

Black onyx
Little or no light gets through
Everyday ring
Tough, scratches over time
Almost always dyed: see the questions below.
Photo: W.carter, CC BY 4.0, via Wikimedia Commons (cropped).
Jet
Little or no light gets through
Everyday ring
Earrings and pendants
Shown here as a rough piece.
Photo: Konto na chwilę, CC BY-SA 4.0, via Wikimedia Commons (cropped).
Obsidian
Little or no light gets through
Everyday ring
Earrings and pendants
Natural glass. Thin edges can let a little light through.
Photo: Stephanie Clifford, CC BY 2.0, via Wikimedia Commons (cropped).
Hematite
Little or no light gets through
Everyday ring
Earrings and pendants
Hematite adds a metallic shine and a surprising weight in the hand.
Photo: Mauro Cateb, CC BY-SA 3.0, via Wikimedia Commons (cropped).
Black sapphire
So dark it reads black
Everyday ring
Yes
Often a very dark greenish blue. The one shown is a black star sapphire.
Black tourmaline
So dark it reads black
Everyday ring
Yes, with care
Often a very dark green or brown. Shown here as an uncut crystal.
Photo: James St. John, CC BY 2.0, via Wikimedia Commons (cropped).
Black spinel
Black by nature
Everyday ring
Yes
Uncut crystals from Sri Lanka, in a museum collection.
Photo: Osama Shukir Muhammed Amin, CC BY-SA 4.0, via Wikimedia Commons (cropped).
Black opal
Black as a background
Everyday ring
Earrings and pendants
Cut and polished black opal from Lightning Ridge, Australia.
Photo: Daniel Mekis, CC BY-SA 3.0, via Wikimedia Commons (cropped).
Tahitian cultured pearl
Black as a background
Everyday ring
Earrings and pendants
A Tahitian cultured pearl can be truly black, with a near-metallic luster.
Photo: Remi Jouan, CC BY-SA 3.0, via Wikimedia Commons (cropped).
Black diamond
A case of its own
Everyday ring
Yes, in a protective setting
Countless tiny black inclusions line the cracks inside a natural black diamond, and that is its color.

Each card shows an example of the stone, not a standard. Uncut crystals and rough pieces are marked as such.

Source: Names, kinds of black and ring use: gemological reference sheets, checked on 27 October 2026. Photo credits are under each card.

Which Black Stones Are Safe in a Ring?

A ring takes scratches and knocks. Dust in the air is mostly quartz, hardness 7, so a stone below 7 slowly loses its polish.

Hard is not always tough

Hardness is resistance to scratches. Toughness is resistance to chips and breaks. Tap a stone.

Toughness (chips and breaks)

Exceptional

Excellent

Good

Fair

Poor

Very poor

23456789101 2 3 4 5 6 7 8

Mohs hardness (scratches)

Touch a point to read about the stone.

Black diamond Mohs 10 · Toughness: Good in the cleavage directions, exceptional in all others

The hardest. A natural black commonly carries fractures, and any diamond can split along a cleavage plane.

Black sapphire Mohs 9 · Toughness: Usually excellent

The easy choice. Black star sapphire is the exception: the inclusions that make its star make it prone to parting.

Black spinel Mohs 8 · Toughness: Good

Hard, with good toughness: a very good ring stone.

Black tourmaline Mohs 7 to 7.5 · Toughness: Fair

A good ring stone: as hard as the dust in the air, with only fair toughness.

Jade Mohs 6 to 7 · Toughness: Exceptional

Softer than dust, yet exceptionally tough: nephrite is the toughest known gem.

Onyx Mohs 6.5 to 7 · Toughness: Good

Tough, which is why it sits in so many signet rings, but years of wear will scratch it.

Opal Mohs 5 to 6.5 · Toughness: Very poor to fair

Softer than dust: keep it for earrings and pendants.

Pearl Mohs 2.5 to 4 · Toughness: Usually good, but variable

Very soft and easily scratched; its toughness varies with age and processing.

Hardness and toughness of eight black stones
Stone	Mohs	Toughness
1Black diamondThe hardest. A natural black commonly carries fractures, and any diamond can split along a cleavage plane.	10	Good in the cleavage directions, exceptional in all others
2Black sapphireThe easy choice. Black star sapphire is the exception: the inclusions that make its star make it prone to parting.	9	Usually excellent
3Black spinelHard, with good toughness: a very good ring stone.	8	Good
4Black tourmalineA good ring stone: as hard as the dust in the air, with only fair toughness.	7 to 7.5	Fair
5JadeSofter than dust, yet exceptionally tough: nephrite is the toughest known gem.	6 to 7	Exceptional
6OnyxTough, which is why it sits in so many signet rings, but years of wear will scratch it.	6.5 to 7	Good
7OpalSofter than dust: keep it for earrings and pendants.	5 to 6.5	Very poor to fair
8PearlVery soft and easily scratched; its toughness varies with age and processing.	2.5 to 4	Usually good, but variable

Points that would overlap are moved apart a little. The exact values are in the table.

Toughness has no number: these are the words gemmologists use. Hematite (5.5 to 6.5), obsidian (5 to 5.5) and jet (2.5 to 4) are not placed: no single toughness grade is given for them. All three are softer than dust.

Source: Hardness and toughness as published in standard gemology references, checked on October 27, 2026.

Opal, hematite, obsidian, pearl and jet belong in earrings and pendants. If an opal is the one you love, read our opal guide first. If black spinel tempts you, see spinel in every color.

Is Your Black Stone Black by Nature?

Several black stones owe their color to treatment. Ask, in writing, before you choose.

Is the black natural? Six questions, ready to send

Tick them as you get answers. The button copies all six, ready to send.

6 points

Onyx: natural black, or dyed?Almost always gray chalcedony turned black by a sugar and acid treatment, usually sold without saying so. Natural black chalcedony is extremely rare.
Diamond: black by nature, or treated?Irradiation leaves it a very dark green or blue; heating can turn its fractures to graphite. Some lab-grown diamonds are irradiated black too.
Pearl: is the color natural?A Tahitian cultured pearl can be naturally black. Akoya pearls are often dyed or irradiated to get there, and freshwater pearls can be.
Opal: solid, doublet or triplet?Sugar and smoke treatments blacken lighter opal, and thin slices are backed with black onyx as doublets or triplets.
Jadeite: heated, filled or dyed?Black jadeite may be heated, impregnated with polymer, or dyed.
A report from an independent laboratory?For any black stone that matters to you, that is where the answer comes from.

A message ready to send to the seller, with all the questions.

See the message

Hello, I am interested in this black stone. Before I choose, could you confirm a few points in writing?

1. If it is onyx: is the black natural, or was the stone dyed?
2. If it is a diamond: is it natural or lab-grown, and is its black natural or the result of irradiation or heating?
3. If it is a pearl: which kind is it, and is its color natural, dyed or irradiated?
4. If it is an opal: is it one solid piece, a doublet or a triplet, and has it been treated with sugar or smoke?
5. If it is jadeite: has it been heated, impregnated with polymer, or dyed?
6. Will it come with a report from an independent laboratory that names the stone and any treatment?

Thank you for your time.

Black diamond also has look-alikes. Black cubic zirconia arrived in the early 1990s to imitate it, and hematite also goes by the false name “black diamond”. For any black stone that matters to you, the answer comes from a report by an independent laboratory: what a lab report proves.

Quick answers

What gemstones are naturally black?

Several. A natural black diamond, black spinel, black tourmaline, jet, obsidian and hematite are black by nature, and a Tahitian cultured pearl can be truly black. Black sapphire is usually a very dark blue or greenish blue that reads black. Black onyx is the exception: almost all of it is dyed.

Which black gemstone is best for an engagement ring?

Black sapphire, black spinel or black diamond, at hardness 9, 8 and 10. Sapphire is the easiest: hard and usually very tough. A natural black diamond is harder still but often fractured inside, so set it to protect the edges. Leave opal and jet for pieces you wear less.

Is black onyx a natural stone?

The stone is natural, the black rarely is. What the trade sells as black onyx is almost always gray chalcedony dyed black with a sugar and acid treatment, usually without saying so. Natural black chalcedony is extremely rare. Dyed onyx is still tough and handsome: just know what you are wearing.

What is the rarest black gemstone?

Fine black opal. It is rare, its dark body makes the play of color stand out more than in any lighter opal, and Lightning Ridge, in Australia, is its major source. The surprise is onyx: natural black chalcedony is extremely rare, which is why nearly every black onyx you see has been dyed.

How can you tell if a black gemstone is real?

Not by eye: black hides most clues. A laboratory reads the refractive index, the weight for its size, and the inclusions under magnification, and shines light through the stone. That is how a very dark sapphire shows its blue. Glass, plastic and black cubic zirconia all imitate black stones.

Choose the black that lasts, then ask where it comes from

For a ring worn every day: sapphire, spinel or diamond. For earrings and pendants, the softer blacks open up, from opal to jet. Whatever the stone, ask whether its black is natural before you choose it.

Describe the black stone you want Start a bespoke request

01Which Gemstones Are Black?