Black Onyx Gemstones

  • Hardness

    7.0 on the Mohs scale.

  • Occurrence

    Found worldwide.

  • Appearance

    Brownish-black to black and opaque. Much black onyx is the brownish variety that has been dyed black. Can be confused with black spinel.

  • Enhancements

    Black onyx is always dyed.

    More information on gemstone enhancements.

  • Gemstone Family

    Black Onyx is a member of the Onyx gemstone family.

Black Onyx
Black Onyx

ONX171
ONX171
 1.77 ct.
8.0mm Round Cut
Black
Opaque
[D] Dyed.
One of a kind.
Black Onyx

ONX174
ONX174
 1.17 ct., 'A' Grade
7.2mm Round Cut
Black
Opaque
[D] Dyed.
One of a kind.
Black Onyx

ONX118
ONX118
 45.49 ct. total
20.0mm Cabochon, Round Cut
Black
Opaque
[D] Dyed.
Quantity Available: 4 pairs
Black Onyx

ONX119
ONX119
 0.16 ct. total
3.0mm Cabochon, Round Cut
Black
Opaque
[D] Dyed.
Only one pair available.
Onyx Chalcedony

ONX173
ONX173
 2.52 ct. total, 'A' Grade
7.0mm Cabochon, Round Cut
Black
Opaque
[D] Dyed.
Only one pair available.
Black Onyx

ONX101
ONX101
 11.60 ct. total
16.0x12.0mm Cabochon, Oval Cut
Black
Opaque
[E] Routinely enhanced.
Only one pair available.
Black Onyx

ONX166
ONX166
 21.02 ct.
25.0x18.0mm Cabochon, Oval Cut
Black
Opaque
[N] Not enhanced.
Quantity Available: 4
Faceted.
Black Onyx

ONX141
ONX141
 0.24 ct. total
3.0x5.0mm Cabochon, Pear Cut
Black
Opaque
[D] Dyed.
Only one pair available.
Black Onyx

ONX142
ONX142
 0.40 ct.
4.0x6.0mm Cabochon, Pear Cut
Black
Opaque
[D] Dyed.
One of a kind.
Black Onyx

ONX132
ONX132
 7.37 ct. total
10.0mm Cabochon, Square Cut
Black
Opaque
[N] Not enhanced.
Quantity Available: 10 pairs
Black Onyx

ONX145
ONX145
 6.88 ct.
12.0mm Cabochon, Square Cut
Black
Opaque
[E] Routinely enhanced.
Quantity Available: 17
black Onyx

ONX133
ONX133
 3.22 ct. total
12.0mm Cabochon, Trillion Cut
Black
Opaque
[N] Not enhanced.
Quantity Available: 5 pairs
Black Onyx

ONX170
ONX170
 2.47 ct.
10.0x8.0mm Antique Cushion, Checkerboard Top Cut
Black
Opaque
[D] Dyed.
One of a kind.
Black Onyx

ONX177
ONX177
 78.28 ct.
45.0mm Donut
Black
Opaque
[D] Dyed.
Quantity Available: 2
Black Onyx

Calibrated Black Onyx
Calibrated Black Onyx

Specify size, shape and quality when ordering. Prices are subject to change without notice. Actual carat weight may vary from the average carat weight listed.

  • A Black, opaque, good polish, good cut.

Black Onyx Quality A
Shape Size Avg. Weight Price Each
Round CutRound Cut
2mm
~
2.5mm
~
3mm
~
4mm
~
5mm
~
6mm
~
7mm
~
8mm
~
9mm
~
10mm
~
 
  A
Oval CutOval Cut
5x3mm
~
6x4mm
~
7x5mm
~
8x6mm
~
9x7mm
~
10x8mm
~
11x9mm
~
12x10mm
~
13x11mm
~
14x10mm
~
14x12mm
~
16x8mm
~
16x12mm
~
18x13mm
~
20x15mm
~
28x16mm
~
 
  A
Pear CutPear Cut
5x3mm
~
6x4mm
~
7x5mm
~
8x5mm
~
9x6mm
~
 
  A
Marquise CutMarquise Cut
4x2mm
~
5x2.5mm
~
6x3mm
~
7x3.5mm
~
8x4mm
~
9x4.5mm
~
10x5mm
~
11x5.5mm
~
12x6mm
~
14x7mm
~
15x7mm
~
16x8mm
~
 
  A
Emerald CutEmerald Cut
5x3mm
~
6x4mm
~
7x5mm
~
8x6mm
~
9x7mm
~
 
  A
Heart ShapeHeart Shape
3mm
~
4mm
~
5mm
~
6mm
~
 
  A
Cabochon, Round CutCabochon, Round Cut
3mm
~
4mm
~
5mm
~
6mm
~
7mm
~
8mm
~
9mm
~
10mm
~
11mm
~
12mm
~
13mm
~
14mm
~
15mm
~
16mm
~
20mm
~
25mm
~
30mm
~
 
  A
Cabochon, Oval CutCabochon, Oval Cut
5x3mm
~
6x4mm
~
7x5mm
~
8x6mm
~
9x7mm
~
10x8mm
~
11x9mm
~
12x10mm
~
13x11mm
~
14x10mm
~
14x12mm
~
16x8mm
~
16x12mm
~
16x14mm
~
17x10mm
~
18x13mm
~
20x15mm
~
22x8mm
~
25x18mm
~
30x22mm
~
40x30mm
~
 
  A
Cabochon, Pear CutCabochon, Pear Cut
5x3mm
~
6x4mm
~
7x5mm
~
8x5mm
~
9x6mm
~
10x7mm
~
12x8mm
~
13x9mm
~
 
  A
Cabochon, Marquise CutCabochon, Marquise Cut
6x3mm
~
8x4mm
~
10x5mm
~
12x6mm
~
15x7mm
~
 
  A
Cabochon, Rectangle CutCabochon, Rectangle Cut
12x10mm
~
 
  A
Cabochon, Heart CutCabochon, Heart Cut
5mm
~
6mm
~
9mm
~
10mm
~
 
  A
Antique CutAntique Cut
5mm
0.50 ct.
6mm
0.80 ct.
 
  A
Antique Cushion CutAntique Cushion Cut
8x6mm
1.30 ct.
9x7mm
1.90 ct.
10x8mm
2.80 ct.
12x10mm
~
14x12mm
~
 
  A
BrioletteBriolette
14x10mm
9.00 ct.
14mm
17.50 ct.
16x8mm
~
22x8mm
~
 
  A
Rectangle, Flat Top CutRectangle, Flat Top Cut
5x3mm
~
6x4mm
~
7x5mm
~
8x6mm
~
9x7mm
~
10x8mm
~
11x9mm
~
12x10mm
~
13x11mm
~
14x10mm
~
14x12mm
~
16x12mm
~
18x13mm
~
 
  A
Roll Top CutRoll Top Cut
10x8mm
2.10 ct.
 
  A
Round, Checkerboard Top CutRound, Checkerboard Top Cut
7mm
1.16 ct.
8mm
1.75 ct.
 
  A
Antique, Checkerboard Top CutAntique, Checkerboard Top Cut
5mm
0.50 ct.
6mm
0.80 ct.
7mm
1.30 ct.
8mm
1.95 ct.
10mm
3.80 ct.
12mm
6.30 ct.
 
  A
Antique Cushion, Checkerboard Top CutAntique Cushion, Checkerboard Top Cut
8x6mm
1.30 ct.
9x7mm
1.90 ct.
10x8mm
2.80 ct.

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