Onyx Beads
Onyx beads are black onyx first: chalcedony dyed and heated to an even, permanent black. Polished rounds read as a wet jet black, matte black onyx as a soft charcoal with no shine, and faceted onyx catches light at every edge. Rounds run 4mm to 12mm, with faceted rondelles, coins, squares, ovals and carved leaves, and green and red onyx are the same chalcedony dyed to color. Beside tiger eye, clear quartz, rose quartz or gold, onyx is the neutral that holds a palette together.
Onyx 10mm Round Step Cut - 15-16 Inch
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$18.00
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Onyx is a black and white banded Chalcedony, a cryptocrystalline Quartz. It is often thought of as an all to black stone, and much of the black Ony...
View full details
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$18.00
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MATTE Onyx 10mm Round - 8-Inch
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Onyx is a black and white banded Chalcedony, a cryptocrystalline Quartz. It is often thought of as an all-black stone, and much of the black Onyx o...
View full details
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$9.00
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Large Hole
Onyx 10mm Round Large Hole 8-Inch
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$14.00
Onyx is a black and white banded Chalcedony, a cryptocrystalline Quartz. It is often thought of as an all-black stone, and much of the black Onyx o...
View full details
Original price
$14.00
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$14.00
Onyx 6mm Round Faceted 8-Inch
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$9.00
Onyx is a black and white banded Chalcedony, a cryptocrystalline Quartz. It is often thought of as an all-black stone, and much of the black Onyx o...
View full details
Original price
$9.00
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$9.00
MATTE Onyx 4mm Round - 8-Inch
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$6.00
Onyx is a black and white banded Chalcedony, a cryptocrystalline Quartz. It is often thought of as an all-black stone, and much of the black Onyx o...
View full details
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$6.00
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MATTE Onyx 8mm Faceted Rondelle 8-Inch
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Onyx is a black and white banded Chalcedony, a cryptocrystalline Quartz. It is often thought of as an all-black stone, and much of the black Onyx o...
View full details
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$15.00
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Onyx 12mm Square 8-Inch
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Onyx is a black and white banded Chalcedony, a cryptocrystalline Quartz. It is often thought of as an all-black stone, and much of the black Onyx o...
View full details
Original price
$11.00
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Onyx 12mm Coin 8-Inch
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Onyx is a black and white banded Chalcedony, a cryptocrystalline Quartz. It is often thought of as an all-black stone, and much of the black Onyx o...
View full details
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$11.00
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Onyx 8mm Star Cut Round 15-16 Inch
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Onyx is a black and white banded Chalcedony, a cryptocrystalline Quartz. It is often thought of as an all-black stone, and much of the black Onyx o...
View full details
Original price
$19.00
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Onyx 6mm Rondelle 8-Inch
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Onyx is a black and white banded Chalcedony, a cryptocrystalline Quartz. It is often thought of as an all-black stone, and much of the black Onyx o...
View full details
Original price
$11.00
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Onyx 8mm Faceted Rondelle 8-Inch
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$14.00
Onyx is a black and white banded Chalcedony, a cryptocrystalline Quartz. It is often thought of as an all-black stone, and much of the black Onyx o...
View full details
Original price
$14.00
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Onyx 6mm Faceted Rondelle 8-Inch
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$14.00
Onyx is a black and white banded Chalcedony, a cryptocrystalline Quartz. It is often thought of as an all-black stone, and much of the black Onyx o...
View full details
Original price
$14.00
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MATTE Onyx 10x14 Oval 8-Inch
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Onyx is a black and white banded Chalcedony, a cryptocrystalline Quartz. It is often thought of as an all-black stone, and much of the black Onyx o...
View full details
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$11.00
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Onyx 40mm Square Donut - Pendant
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Onyx is a black and white banded Chalcedony, a cryptocrystalline Quartz. It is often thought of as an all to black stone, and much of the black Ony...
View full details
Original price
$9.00
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$9.00
MATTE Onyx 12mm Coin 8-Inch
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$11.00
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Onyx is a black and white banded Chalcedony, a cryptocrystalline Quartz. It is often thought of as an all-black stone, and much of the black Onyx o...
View full details
Original price
$11.00
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$11.00
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Black Eye Agate 10mm Round 15-16 Inch
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Black Eye Agate is a variety of Sardonyx which has a Sard base, typically of brown or black, with bands of white Onyx running through it. Sard is n...
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Onyx 7x8mm Faceted Rice Bead - 15-16 Inch
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Onyx is a black and white banded Chalcedony, a cryptocrystalline Quartz. It is often thought of as an all to black stone, and much of the black Ony...
View full details
Original price
$18.00
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Original price
$18.00
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$18.00
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$18.00
Large Hole
Onyx 8mm Faceted Rondelle Large Hole 8-Inch
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$19.00
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Onyx is a black and white banded Chalcedony, a cryptocrystalline Quartz. It is often thought of as an all-black stone, and much of the black Onyx o...
View full details
Original price
$19.00
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$19.00
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Green Onyx 8x11mm Leaf - 8 Inch
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$95.00
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Onyx is a black and white banded Chalcedony, a cryptocrystalline Quartz. It is often thought of as an all to black stone, and much of the black Ony...
View full details
Original price
$95.00
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Original price
$95.00
Original price
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Onyx 8x11mm Leaf - 8 Inch
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$95.00
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$95.00
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$95.00
Onyx is a black and white banded Chalcedony, a cryptocrystalline Quartz. It is often thought of as an all to black stone, and much of the black Ony...
View full details
Original price
$95.00
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Original price
$95.00
Original price
$95.00
$95.00
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$95.00
Red Onyx 8x11mm Leaf - 8 Inch
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$95.00
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$95.00
Onyx is a black and white banded Chalcedony, a cryptocrystalline Quartz. It is often thought of as an all to black stone, and much of the black Ony...
View full details
Original price
$95.00
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Original price
$95.00
Original price
$95.00
$95.00
$95.00
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$95.00
Current price
$95.00
Black onyx — the even black, polished to a glass shine
Onyx is chalcedony, quartz in a grain too fine to see, dense and opaque, and it takes the highest polish of the black stones: polished rounds and rondelles show a glassy, wet-looking jet black with no cloud or banding. The color is carbon fixed inside the stone by the sugar-and-acid treatment the trade has used for well over a century — natural onyx is banded black and white, and solid black is made. At Mohs 6.5–7 it wears daily and keeps its polish.
Matte black onyx, green and red onyx — finishes and colors
A matte, frosted finish turns the same bead into a soft charcoal-black with no reflection, sold as matte black onyx in the same sizes as the polished strands. Green onyx and red onyx are the same chalcedony dyed to color rather than black, recorded as dyed and heated. Natural onyx is banded — black and white, or with red-brown sard layers as sardonyx. The green and blue "onyx" of lamps and countertops is banded calcite, a softer stone that carries the name by trade habit.
Faceted onyx, rounds and coins — sizes and cuts, 4mm to 12mm
Onyx is hard-wearing (Mohs 6.5–7): mild soap and a soft cloth, no ultrasonic or steam, and out of prolonged direct sun. Faceted onyx carries the most light — faceted rounds, star cut and step cut at 6mm to 10mm, faceted rondelles 4mm to 8mm, faceted rice and nuggets. Smooth rounds run 4mm to 12mm, 8mm and 10mm the mala sizes; coins 12mm and 15mm, squares, ovals, carved leaves, large-hole rounds at 8mm and 10mm, cabochons and 40mm donuts. It pairs with tiger eye, clear quartz, rose quartz and gold.
About this stone
Color
BlackWhiteBanded Black-and-White
Origin
MexicoPakistanBrazilMadagascarUruguay
Mohs hardness
6.5–7
Treatment categories
DyedHeatedNatural
Industry-standard treatment
Most commercial black onyx is dyed chalcedony; banded natural onyx is also available
Mineral chemistry
Chalcedony (cryptocrystalline quartz) with parallel banding
Crystal system
Trigonal
Stone family
Chalcedony
Common cuts
RoundFaceted RoundRondelle
Common sizes
4mm6mm8mm10mm
Care notes
Durable (Mohs 6.5–7). Mild soap and soft cloth; dyed material can fade with prolonged sun exposure.
Related stones
Sardonyx, Agate, Carnelian, Chalcedony
Frequently asked questions
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Is black onyx dyed?
Yes. Nearly all black onyx in the bead trade is chalcedony treated to a uniform black: the stone is soaked in a sugar solution, then in sulfuric acid, and the acid converts the sugar to carbon inside the stone's pores. The method is well over a century old and is recognized as a stable, permanent treatment. The black is inside the stone, not a coating, so it does not rub off or wash out; like any dyed stone it is kept out of prolonged direct sun. Natural solid-black chalcedony is rare — natural onyx is banded — and treatment is recorded on each strand. -
What is the difference between black onyx and black agate?
In the bead trade, very little. Both names usually mean the same dyed-and-heated chalcedony, and which one a strand carries follows the supplier. Older lapidary usage kept them apart by banding: onyx for straight, parallel black-and-white layers, agate for curved or concentric ones, and a natural black-and-white banded stone is still sold as banded onyx, tuxedo agate or black eye agate. For solid black beads the two names are interchangeable; size, cut, finish and the recorded treatment are what differ. -
What is the difference between black onyx and obsidian?
They are different materials. Black onyx is dyed-and-heated chalcedony — microcrystalline quartz, Mohs 6.5–7. Obsidian is volcanic glass, non-crystalline, Mohs 5–5.5, formed when lava cools too fast to crystallize. Both are a deep glossy black, but obsidian is often slightly translucent at the edges and breaks with the curved, shell-like fracture of glass, while onyx is uniformly opaque. Onyx is the harder and more scratch-resistant of the two; obsidian chips more easily at drill holes and facet edges. -
Is green onyx real onyx?
In beads, usually yes. Green onyx and red onyx bead strands are the same chalcedony as black onyx, dyed to a color instead of black, and recorded as dyed. The green onyx of lamps, bookends and countertops is a different stone: banded calcite, sold as onyx marble or Mexican onyx, at Mohs 3 soft enough to scratch with a knife where chalcedony onyx is 6.5–7. Most "blue onyx" is calcite as well. Calcite is carved and strung too, but it is softer and is sold under its own name. -
Which onyx bead sizes are used for malas and bracelets?
By size. 8mm is the standard mala round — 108 beads plus a guru bead string to about 34 inches — and the most common bracelet size; 6mm makes a finer mala or a stacking bracelet, 10mm a heavier bracelet, and 4mm rounds work as spacers. An 8-inch strand of 8mm rounds is one bracelet, roughly 25 beads; a 16-inch strand is two. Large-hole 8mm and 10mm rounds take leather, cord or doubled stretch cord. Matte and polished come in the same sizes, so a piece can mix the two finishes.