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Home › Calibrated Gemstones › Octagon Shape 27 x 20 mm Gems

Calibrated 27 x 20 mm Octagon Shape Gemstones | GemSelect

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12.30ct Natural Black Onyx, Pear Shape, Opaque, Photo A

12.30ct Natural Black Onyx, Pear Shape, Opaque

Onyx

12.30ct1 pc
$ 24.50
20 x 15 mm (calibrated)
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7.22ct Natural Blue Green Grandidierite, Oval, Translucent, Photo A
Grandidierite Product Video (471995)

7.22ct Natural Blue Green Grandidierite, Oval, Translucent

Grandidierite

7.22ct1 pc
$ 1,582.05
13.9 x 10.7 mm
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0.44ct Natural Bright Pink Spinel, Cushion, VS, Photo A

0.44ct Natural Bright Pink Spinel, Cushion, VS

Spinel

0.44ct1 pc
$ 30.68
4.7 x 4 mm
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0.99ct Natural Medium-Dark Red Rhodolite Garnet, Oval, VS, Photo A

0.99ct Natural Medium-Dark Red Rhodolite Garnet, Oval, VS

Rhodolite Garnet

0.99ct1 pc
$ 21.70
7 x 5 mm (calibrated)
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0.58ct Natural Bright Orange Spessartite Garnet, Oval, VS-SI, Photo A

0.58ct Natural Bright Orange Spessartite Garnet, Oval, VS-SI

Spessartite Garnet

0.58ct1 pc
$ 17.33
5 x 4 mm (calibrated)
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7.49ct Natural Dark Brown Smoky Quartz, Octagon / Emerald Cut, VVS-VS, Photo A

7.49ct Natural Dark Brown Smoky Quartz, Octagon / Emerald Cut, VVS-VS

Smoky Quartz

7.49ct1 pc
$ 9.27
12 x 12 mm (calibrated)
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0.70ct Natural Yellowish Green Sapphire, Cushion, VS-SI, Photo A

0.70ct Natural Yellowish Green Sapphire, Cushion, VS-SI

Sapphire

0.70ct1 pc
$ 55.78
5.6 x 4.4 mm
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1.62ctw Natural Medium Green Peridot, Oval, VS, Photo A

1.62ctw Natural Medium Green Peridot, Oval, VS

Peridot

1.62ct total2 pcs
$ 11.30
7 x 5 mm (calibrated)
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0.51ct Natural Dark Green Chrome Diopside, Oval, VVS-VS, Photo A

0.51ct Natural Dark Green Chrome Diopside, Oval, VVS-VS

Chrome Diopside

0.51ct1 pc
$ 12.70
6 x 4 mm (calibrated)
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88.10ct Natural London Blue Topaz, Oval, IF, Photo A
Topaz Product Video (668000)

88.10ct Natural London Blue Topaz, Oval, IF

Topaz

88.10ct1 pc
$ 614.23
28.1 x 25.5 mm
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10.12ctw Natural Medium Violet Amethyst, Oval, Transparent, Photo A

10.12ctw Natural Medium Violet Amethyst, Oval, Transparent

Amethyst

10.12ct total2 pcs
$ 55.44
12 x 10 mm (calibrated)
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0.93ct Natural Pinkish Red Ruby, Pear Shape, VS-SI, Photo A

0.93ct Natural Pinkish Red Ruby, Pear Shape, VS-SI

Ruby

0.93ct1 pc
$ 83.37
7 x 5 mm (calibrated)
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0.97ct Natural Bright Green Emerald, Oval, Translucent, Photo A

0.97ct Natural Bright Green Emerald, Oval, Translucent

Emerald

0.97ct1 pc
$ 77.29
6.8 x 5.8 mm
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16.22ctw Natural Earthy Green Seraphinite, Baguette, Opaque, Photo A

16.22ctw Natural Earthy Green Seraphinite, Baguette, Opaque

Seraphinite

16.22ct total2 pcs
$ 26.30
14 x 10 mm (calibrated)
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0.47ct Natural Medium Golden Citrine, Heart, VS, Photo A

0.47ct Natural Medium Golden Citrine, Heart, VS

Citrine

0.47ct1 pc
$ 3.74
5.2 x 5.2 mm
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0.78ct Natural Brick Red Tourmaline, Pear Shape, VVS, Photo A

0.78ct Natural Brick Red Tourmaline, Pear Shape, VVS

Tourmaline

0.78ct1 pc
$ 32.37
8 x 6 mm (calibrated)
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0.34ct Natural Intense Orange Spessartite Garnet, Oval, VS, Photo A

0.34ct Natural Intense Orange Spessartite Garnet, Oval, VS

Spessartite Garnet

0.34ct1 pc
$ 11.85
4.9 x 3.2 mm
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13.93ctw Natural Black Spinel, Round, Opaque, Photo A

13.93ctw Natural Black Spinel, Round, Opaque

Spinel

13.93ct total2 pcs
$ 45.78
12 mm (calibrated)
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9.51ctw Natural Deep Rose Pink Strawberry Quartz, Oval, Transparent, Photo A

9.51ctw Natural Deep Rose Pink Strawberry Quartz, Oval, Transparent

Strawberry Quartz

9.51ct total2 pcs
$ 145.86
12 x 10 mm (calibrated)
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9.47ct Natural Black Onyx, Pear Shape, Opaque, Photo A

9.47ct Natural Black Onyx, Pear Shape, Opaque

Onyx

9.47ct1 pc
$ 9.43
18 x 13 mm (calibrated)
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0.05ct Natural Blue Diamond, Round, VS, Photo A

0.05ct Natural Blue Diamond, Round, VS

Diamond

0.05ct1 pc
$ 55.89
2.4 mm (calibrated)
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0.82ct Natural Deep Azure Blue Kyanite, Round, SI, Photo A

0.82ct Natural Deep Azure Blue Kyanite, Round, SI

Kyanite

0.82ct1 pc
$ 24.96
5.2 mm
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1.98ct Natural Warm Brown Tiger's Eye, Pear Shape, Opaque, Photo A

1.98ct Natural Warm Brown Tiger's Eye, Pear Shape, Opaque

Tiger's Eye

1.98ct1 pc
$ 2.56
8 x 8 mm (calibrated)
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22.22ct Natural Grayish Green Jadeite, Oval, Translucent, Photo A

22.22ct Natural Grayish Green Jadeite, Oval, Translucent

Jadeite

22.22ct1 pc
$ 73.04
25 x 18 mm (calibrated)
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3.20ctw Natural Medium-Light Green Sapphire, Oval, VVS-VS, Photo A

3.20ctw Natural Medium-Light Green Sapphire, Oval, VVS-VS

Sapphire

3.20ct total4 pcs
$ 140.24
6 x 4.9 mm
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27.96ct Natural Schorl Tourmaline, Cushion, Opaque, Photo A

27.96ct Natural Schorl Tourmaline, Cushion, Opaque

Tourmaline

27.96ct1 pc
$ 99.42
18.8 x 16.1 mm
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0.49ct Natural Multicolor Chocolate Opal, Oval, Translucent, Photo A

0.49ct Natural Multicolor Chocolate Opal, Oval, Translucent

Chocolate Opal

0.49ct1 pc
$ 16.10
7.4 x 5.2 mm
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0.59ct Natural Very Light Purple Spinel, Round, VS, Photo A

0.59ct Natural Very Light Purple Spinel, Round, VS

Spinel

0.59ct1 pc
$ 30.93
4.7 mm
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1.19ct Natural Medium Red Ruby, Pear Shape, VS-SI, Photo A

1.19ct Natural Medium Red Ruby, Pear Shape, VS-SI

Ruby

1.19ct1 pc
$ 106.67
8 x 6 mm (calibrated)
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1.97ct Natural Light Violet Amethyst, Square, VS, Photo A

1.97ct Natural Light Violet Amethyst, Square, VS

Amethyst

1.97ct1 pc
$ 15.70
7.6 x 7.6 mm
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6.08ct Natural Medium Violet Amethyst, Pear Shape, VS, Photo A

6.08ct Natural Medium Violet Amethyst, Pear Shape, VS

Amethyst

6.08ct1 pc
$ 46.23
16 x 12 mm (calibrated)
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3.33ctw Natural Dark Red Pyrope Garnet, Square, VS, Photo A

3.33ctw Natural Dark Red Pyrope Garnet, Square, VS

Pyrope Garnet

3.33ct total10 pcs
$ 25.54
3.9 x 3.7 mm
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Why Buy Octagon Shape 27 X 20 Mm Gems from GemSelect?

GemSelect Certified Store Reviews

GemSelect: Over 22 Years in the Gemstone Business! Thank you for trusting us with your purchase!

Overall Rating -> 10 star ratings

I had a very easy time navigating the web page and using filters to find what I was looking for. The varied selection was nice to see and pricing is clear and fair.

Posted By Mattick in May, 2026
Source: Bizrate

Overall Rating -> 10 star ratings

My current project is something BLUE . Opal earrings with matching tennis bracelet for her wedding. The opals and sixty two sapphires VVS & VS are AMAZINGLY BEAUTIFUL. The private jewelers were impressed by the clarity and inclusion free of the sapphires . I want to say thank you for the High quality sapphires that I purchased for my daughtera's wedding.

Posted By My real name Dean or Wandering about in May, 2026
Source: Bizrate

Overall Rating -> 10 star ratings

I found the filter options excellent. Yours was the third site I visited (asked chat got for reputable online sellers of loose gems) and the first I purchased from as I was able to easily find what I was looking for.

Posted By Kelly in May, 2026
Source: Bizrate

Overall Rating -> 10 star ratings

The website has a good selection, the interface is very intuitive.

Posted By PhoenixFeatherJewelry in January, 2026
Source: Bizrate

Overall Rating -> 10 star ratings

The citrine gems are beautiful. I appreciated that each stone was individually shown on the website so I could see exactly what I was getting. No mystery person selecting random stones for me. The documentation included with each gem was high quality as well. Great price and arrived as expected.

Posted By Jen in December, 2025
Source: Bizrate

Overall Rating -> 9 star ratings

Ita's a pretty good and simple way to find gems that youa're looking for amazing selection

Posted By Amman in May, 2026
Source: Bizrate
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