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Buy Octagon Shape 27 x 20 mm Gems

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30.23ctw Natural Multicolor Fossil Coral, Cushion, Opaque, Photo A

30.23ctw Natural Multicolor Fossil Coral, Cushion, Opaque

Fossil Coral

30.23ct total2 pcs
$ 47.09
18.3 x 13.9 mm
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8.02ct Natural Autumn Yellow Apatite, Pear Shape, VS, Photo A
Apatite Product Video (385929)

8.02ct Natural Autumn Yellow Apatite, Pear Shape, VS

Apatite

8.02ct1 pc
$ 510.26
16 x 12 mm (calibrated)
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1.09ct Natural Dark Brown Smoky Quartz, Round, VVS, Photo A

1.09ct Natural Dark Brown Smoky Quartz, Round, VVS

Smoky Quartz

1.09ct1 pc
$ 6.54
7 mm (calibrated)
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1.15ct Natural Very Light Yellow Color-Change Diaspore, Pear Shape, VS-SI, Photo A

1.15ct Natural Very Light Yellow Color-Change Diaspore, Pear Shape, VS-SI

Color-Change Diaspore

1.15ct1 pc
$ 73.84
8.5 x 5.2 mm
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1.24ctw Natural Bluish White Rainbow Moonstone, Oval, Transparent, Photo A

1.24ctw Natural Bluish White Rainbow Moonstone, Oval, Transparent

Rainbow Moonstone

1.24ct total2 pcs
$ 25.30
7 x 5 mm (calibrated)
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36.38ct Natural Light Yellow Quartz, Oval, Transparent, Photo A

36.38ct Natural Light Yellow Quartz, Oval, Transparent

Quartz

36.38ct1 pc
$ 57.64
25 x 18 mm (calibrated)
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0.55ct Natural Bright Orange Sapphire, Oval, VS, Photo A

0.55ct Natural Bright Orange Sapphire, Oval, VS

Sapphire

0.55ct1 pc
$ 70.07
6 x 4 mm (calibrated)
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1.47ct Natural Bright Green Sphene, Oval, Transparent, Photo A

1.47ct Natural Bright Green Sphene, Oval, Transparent

Sphene

1.47ct1 pc
$ 8.82
7.4 x 5.7 mm
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3.67ctw Natural Multicolor Labradorite, Round, Translucent, Photo A

3.67ctw Natural Multicolor Labradorite, Round, Translucent

Labradorite

3.67ct total2 pcs
$ 10.74
7 mm (calibrated)
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0.57ct Natural Multicolor Opal, Pear Shape, Transparent, Photo A

0.57ct Natural Multicolor Opal, Pear Shape, Transparent

Opal

0.57ct1 pc
$ 17.10
8 x 5 mm (calibrated)
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2.05ctw Natural Pastel Blue Sapphire, Square, VVS-VS, Photo A

2.05ctw Natural Pastel Blue Sapphire, Square, VVS-VS

Sapphire

2.05ct total30 pcs
$ 162.36
2.2 x 2.2 mm
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1.40ctw Natural Deep Red Pyrope Garnet, Square, VS, Photo A

1.40ctw Natural Deep Red Pyrope Garnet, Square, VS

Pyrope Garnet

1.40ct total2 pcs
$ 12.94
5 x 5 mm (calibrated)
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1.35ctw Natural Dark Blue Kyanite, Round, VS-SI, Photo A

1.35ctw Natural Dark Blue Kyanite, Round, VS-SI

Kyanite

1.35ct total2 pcs
$ 33.86
5.2 mm
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2.07ctw Natural Light Navy Blue Kyanite, Oval, SI, Photo A

2.07ctw Natural Light Navy Blue Kyanite, Oval, SI

Kyanite

2.07ct total2 pcs
$ 51.91
7 x 5 mm (calibrated)
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1.10ctw Natural London Blue Topaz, Oval, VVS-VS, Photo A

1.10ctw Natural London Blue Topaz, Oval, VVS-VS

Topaz

1.10ct total2 pcs
$ 10.56
6.2 x 4.2 mm
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1.41ct Natural Peach Orange Moonstone, Trillion, Translucent, Photo A

1.41ct Natural Peach Orange Moonstone, Trillion, Translucent

Moonstone

1.41ct1 pc
$ 3.38
8 x 7.7 mm
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4.12ct Natural Deep Golden Orange Citrine, Cushion, VVS-VS, Photo A

4.12ct Natural Deep Golden Orange Citrine, Cushion, VVS-VS

Citrine

4.12ct1 pc
$ 38.06
12.2 x 8.4 mm
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4.79ctw Natural Deep Red Pyrope Garnet, Marquise, VS, Photo A

4.79ctw Natural Deep Red Pyrope Garnet, Marquise, VS

Pyrope Garnet

4.79ct total4 pcs
$ 50.58
10 x 5.1 mm
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4.57ct Natural Multicolor Fire Agate, Fancy, Opaque, Photo A

4.57ct Natural Multicolor Fire Agate, Fancy, Opaque

Fire Agate

4.57ct1 pc
$ 42.34
10.9 x 9.9 mm
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58.32ct Natural Intense Violet Amethyst, Oval, VS, Photo A
Amethyst Product Video (638843)

58.32ct Natural Intense Violet Amethyst, Oval, VS

Amethyst

58.32ct1 pc
$ 489.89
26.3 x 23.5 mm
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6.22ct Natural Wood Brown Smoky Quartz, Marquise, VVS, Photo A

6.22ct Natural Wood Brown Smoky Quartz, Marquise, VVS

Smoky Quartz

6.22ct1 pc
$ 52.25
25.2 x 9.1 mm
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36.66ct Natural Multicolor Jasper, Fancy, Translucent, Photo A

36.66ct Natural Multicolor Jasper, Fancy, Translucent

Jasper

36.66ct1 pc
$ 34.85
45.9 x 26.3 mm
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9.73ctw Natural Dark Violet Amethyst, Oval, Transparent, Photo A

9.73ctw Natural Dark Violet Amethyst, Oval, Transparent

Amethyst

9.73ct total2 pcs
$ 64.22
12 x 10 mm (calibrated)
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1.62ct Natural Bluish White Rainbow Moonstone, Oval, Transparent, Photo A

1.62ct Natural Bluish White Rainbow Moonstone, Oval, Transparent

Rainbow Moonstone

1.62ct1 pc
$ 33.23
9 x 7 mm (calibrated)
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2.73ct Natural Medium Yellow Apatite, Octagon / Emerald Cut, VS, Photo A
Apatite Product Video (439100)

2.73ct Natural Medium Yellow Apatite, Octagon / Emerald Cut, VS

Apatite

2.73ct1 pc
$ 169.37
8.6 x 8.5 mm
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1.34ctw Natural Golden Citrine, Trillion, VVS-VS, Photo A

1.34ctw Natural Golden Citrine, Trillion, VVS-VS

Citrine

1.34ct total2 pcs
$ 12.38
6 x 6 mm (calibrated)
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0.87ct Natural Sky Blue Topaz, Pear Shape, VS, Photo A

0.87ct Natural Sky Blue Topaz, Pear Shape, VS

Topaz

0.87ct1 pc
$ 8.04
7 x 5 mm (calibrated)
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3.07ct Natural Medium Gold Citrine, Oval, VS, Photo A

3.07ct Natural Medium Gold Citrine, Oval, VS

Citrine

3.07ct1 pc
$ 29.47
12 x 10 mm (calibrated)
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2.46ct Natural Multicolor Opal, Oval, Opaque, Photo A

2.46ct Natural Multicolor Opal, Oval, Opaque

Opal

2.46ct1 pc
$ 88.56
10.9 x 8 mm
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35.50ct Natural Multicolor Jasper, Oval, Opaque, Photo A

35.50ct Natural Multicolor Jasper, Oval, Opaque

Jasper

35.50ct1 pc
$ 26.71
30.4 x 23 mm
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9.19ct Natural Swiss Blue Topaz, Flower Cut, Transparent, Photo A

9.19ct Natural Swiss Blue Topaz, Flower Cut, Transparent

Topaz

9.19ct1 pc
$ 60.66
20.1 x 12.7 mm
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3.02ctw Natural White Zircon, Oval, VVS, Photo A

3.02ctw Natural White Zircon, Oval, VVS

Zircon

3.02ct total2 pcs
$ 21.73
7 x 5 mm (calibrated)
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GemSelect Certified Store Reviews

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

Overall Rating -> 7 star ratings

Excited to see

Posted By Ss in December, 2024
Source: Bizrate

Overall Rating -> 10 star ratings

I was looking for a site with every type of gem I could want for setting in luxury blades and assumed I would need to look outside the US, but GemSelect made it easy to get everything I wanted without leaving the house! Wide enough selection that I do not feel the need to look elsewhere and pricing the same.

Posted By Razormane in April, 2025
Source: Bizrate

Overall Rating -> 10 star ratings

I have ordered from Genselect before and always had a great experience. My go to source!

Posted By Kycaver in October, 2024
Source: Bizrate

Overall Rating -> 10 star ratings

Love beauty, color, quality, and price of these gems. Personal projects and will come here soon and everytime.

Posted By Darkstar in June, 2025
Source: Bizrate

Overall Rating -> 10 star ratings

Excellent selection and easy to use, well done site

Posted By Steph in December, 2024
Source: Bizrate

Overall Rating -> 10 star ratings

Always find more niche sizes/shapes as my unconventional designs require from this website. Recommending to fellow designers in the creative atmosphere on the usual, specially due to the quality and certification of gems.

Posted By Sina in April, 2025
Source: Bizrate

Overall Rating -> 10 star ratings

Great for buying gemstones, came with authenticity certs. Will buy again someday!

Posted By Uggadugga in May, 2025
Source: Bizrate

Overall Rating -> 10 star ratings

I searched for the size, dimensions and quality of the stones I was looking for and then compared and ordered.

Posted By Tim in March, 2025
Source: Bizrate

Overall Rating -> 10 star ratings

Very fast navigation and purchase, which is good. I need to strike while the iron is hot.

Posted By Tim G. in February, 2025
Source: Bizrate

Some people by gems by color or price, but for many, it is best to buy gems by shape and size - especially if you're in need of a gem to replace a previous item that was lost or damaged. Calibrated Octagon Shape / Emerald-Cut, faceted and cabochon gems available now in 27 x 20 mm size range. Shop a wide range of calibrated gemstones by size online at wholesale from GemSelect.

As a general guideline, when it comes to 'calibrated' gems, they are not usually expected to be cut to exact measurements. For calibrated gemstones weighing under one carat, most jewelry settings will accommodate a gem which is within 0.2 mm of the calibrated size in order to fit a standard setting. For gemstones that weigh over one carat, a larger variance is acceptable, often round shape settings will allow 0.3 mm or slightly higher even. This small variance can usually be accommodated for most standard style settings. Round-cut gemstones should also have a greater variance in acceptable size when it comes to calibration; in fact it is usually possible to mount a round stone of any size in the closest standard setting.

Read All

Over 19 Years in the Gemstone Business!

Thank you for trusting us with your purchase!

Overall Rating -> 7 star ratings

Excited to see

Posted By Ss in December, 2024
Source: Bizrate

Overall Rating -> 10 star ratings

I was looking for a site with every type of gem I could want for setting in luxury blades and assumed I would need to look outside the US, but GemSelect made it easy to get everything I wanted without leaving the house! Wide enough selection that I do not feel the need to look elsewhere and pricing the same.

Posted By Razormane in April, 2025
Source: Bizrate

Overall Rating -> 10 star ratings

I have ordered from Genselect before and always had a great experience. My go to source!

Posted By Kycaver in October, 2024
Source: Bizrate

Overall Rating -> 10 star ratings

Love beauty, color, quality, and price of these gems. Personal projects and will come here soon and everytime.

Posted By Darkstar in June, 2025
Source: Bizrate

Overall Rating -> 10 star ratings

Excellent selection and easy to use, well done site

Posted By Steph in December, 2024
Source: Bizrate

Overall Rating -> 10 star ratings

Always find more niche sizes/shapes as my unconventional designs require from this website. Recommending to fellow designers in the creative atmosphere on the usual, specially due to the quality and certification of gems.

Posted By Sina in April, 2025
Source: Bizrate

Overall Rating -> 10 star ratings

Great for buying gemstones, came with authenticity certs. Will buy again someday!

Posted By Uggadugga in May, 2025
Source: Bizrate

Overall Rating -> 10 star ratings

I searched for the size, dimensions and quality of the stones I was looking for and then compared and ordered.

Posted By Tim in March, 2025
Source: Bizrate

Overall Rating -> 10 star ratings

Very fast navigation and purchase, which is good. I need to strike while the iron is hot.

Posted By Tim G. in February, 2025
Source: Bizrate
Enlarged Gemstone Image