Calibrated 20 x 15 mm Octagon Shape Natural Gemstones: GemSelect

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 20 x 15 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.

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Overall Rating -> 10

I have actually done business with them before and was quite satisfied with them then.My Mother collected turtle items and when I saw the Mother of Pearl turtle...I just thought of her and decided to buy it. It's even tinier than I thought, but so adorable!The gemstones I bought are for jewelry for my daughter's birthday.

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Overall Rating -> 10

Very large selection of items and we used the stones to have several pieces of jewelry made for us.

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Overall Rating -> 10

I had a great time searching all the lovely stones. This is my first precious loose stone purchase for my own work. I chose sapphire, and found some lovely briolettes. I wanted 3, but this set of 4 was perfect. Everything was quick and easy, and I'm excited.

Posted By Phoenix in February, 2024

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Overall Rating -> 10

Best place to buy gem stones, dont bother shopping else where. Prices are great, no issues with shipping and customer service is the best.

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Overall Rating -> 10

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The website is user friendly, has excellent selection. I've always found what I was looking for with Gem Select. When others don't have it they do. And most important, they have a way for you to pay without using PayPal. I cannot use PayPal they closed my account because of no cell phone.

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Overall Rating -> 9

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Gemstones A-Z

Buy Octagon Shape 20x15 mm Gems

3.17 ct Round Cut Peridot, 5.1 mm From China

7.03 ct Round Quartz Cat's Eye, 11.6 mm From India

1.61 ct Yellow Sillimanite, 8.1 x 6.1 mm Oval Cut From Sri Lanka

2.31 carat Orange Hessonite Garnet, Cushion loose Hessonite Garnet from Sri Lanka, Natural Untreated Gem, 7.6 x 7.5 mm

16.08 ct Oval Buff Top Chalcedony, 15.5 x 11.7 mm From Brazil

1.82 ct Loose Orange Moonstone, 10.2 x 5.1 mm Marquise Cut From India

0.91 ct Octagon Cut Color-Change Diaspore, 6.3 x 4.3 mm From Turkey

0.55 ct Octagon Cut Peridot, 5.8 x 4 mm From China

1.04 ct Yellow Diamond, 6.4 x 5.1 mm Odd Shaped From South Africa

2.4 ct Oval Cut Peridot, 8.8 x 7.1 mm From Myanmar

22.65 ct Oval Rose Quartz, 19.8 x 16.5 mm From South Africa

1.01 carat Yellow Citrine, Emerald Cut loose Citrine from Brazil, Natural Untreated Gem, 12.1 x 4.1 mm

0.76 carat Oval Peridot, loose Certified Peridot from China, Natural Untreated Gem, 7 x 5 mm

2.84 carat Swiss Blue Topaz, Fancy-Cut loose Topaz from Brazil, Natural Gems, 10.1 x 4.9 mm

4.57 carat Pear Shape Amethyst, loose Certified Amethyst from Brazil, Natural Untreated Gem, 13.9 x 10 mm

1.72 carat Blue Tanzanite, Pear Shape loose Tanzanite from Tanzania, Natural Gems, 5.2 x 3.2 mm

0.55 ct Octagon Cut Peridot, 5.9 x 4 mm From China

6.93 carat Black Tourmaline, Oval loose Tourmaline from Mozambique, Natural Untreated Gem, 13.7 x 11.4 mm

1.97 carat Orange Hessonite Garnet, Oval loose Hessonite Garnet from Madagascar, Natural Untreated Gem, 8.2 x 7 mm

1.62 carat Blue Sapphire, Princess-Cut loose Sapphire from Madagascar, Natural Gems, 2.3 x 2.3 mm

1.33 carat Square Rhodolite Garnet, loose Certified Rhodolite Garnet from Mozambique, Natural Untreated Gems, 4.9 x 4.9 mm

16.54 ct Green Jadeite, 21.2 x 16.6 mm Oval Cut From Myanmar

0.66 carat London Blue Topaz, Oval loose Topaz from Brazil, Natural Gem, 6.2 x 4.2 mm

2.3 carat Square Rhodolite Garnet, loose Certified Rhodolite Garnet from Mozambique, Natural Untreated Gems, 4.7 x 4.6 mm

2.75 carat White Zircon, Oval loose Zircon from Cambodia, Natural Gem, 9.4 x 6.3 mm

5.01 carat Pear Shape Amethyst, loose Certified Amethyst from Brazil, Natural Untreated Gem, 13.8 x 10 mm

0.41 ct Pink Spinel, 4.7 x 3.7 mm Cushion Cut From Tanzania

4 carat Marquise Cut Pyrope Garnet, loose Certified Pyrope Garnet from Mozambique, Natural Untreated Gems, 12 x 6 mm

236.3 ct Oval Star Rose Quartz, 38.2 x 36.2 mm From South Africa

0.57 ct Loose Purple Sapphire, 5.9 x 4.8 mm Oval Cut From Tanzania

2.49 carat White Zircon, Diamond-Cut loose Zircon from Myanmar, Natural Gems, 6 mm

0.14 carat Baguette Cut Emerald, loose Certified Emerald from Colombia, Natural Gem, 4 x 2 mm

Gemstone Information

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