Calibrated Size for Octagon Cut Gemstones 16x12 mm

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 16 x 12 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

Gemstone Information

Over 19 Years in the Gemstone Business!

Thank you for trusting us with your purchase!

Overall Rating -> 10

the searching format was easy to find what i needed. It helped to be able to sort Lowest price to Highest because i wasnt looking to spend too much but i did want an actual stone and not imitation.

Posted By PixelComposer in January, 2024

Source: Bizrate

Overall Rating -> 10

Excellent experience!

Posted By Steph in April, 2023

Source: Bizrate

Overall Rating -> 10

Easy to use website, made it very easy to buy. Will shop here again.

Posted By Bjorn in January, 2024

Source: Bizrate

Overall Rating -> 10

I have had and will always have a great time shopping at GemSelect. It's a great web site with great products and great service.

Posted By Apps in November, 2023

Source: Bizrate

Overall Rating -> 10

Easy to use,I have spent many hours looking at the site

Posted By Skip in November, 2023

Source: Bizrate

Overall Rating -> 10

I really enjoy browsing through GemSelect. The selection is always marvelous and I love how detailed everything is described. The only thing I noticed is that when browsing through my phone, the videos of the gems do not load. If there were more videos of the gems, that would be amazing, though I understand that is a lot of work on GemSelect's part! Checking out is also very fast and easy, and I love that the return policy is very good, though I hope I don't have to use it anytime soon.

Posted By ChiChi in January, 2024

Source: Bizrate

Overall Rating -> 8

Very easy to find the specific stone I was looking for. I am pleased by both the selection and the price of the stones that are available. The only "bad" thing that I have to say is that the interface of the site is outdated.

Posted By Nick in March, 2024

Source: Bizrate

Overall Rating -> 9

Good interaction with site

Posted By Brick in September, 2023

Source: Bizrate

Overall Rating -> 10

Easy to find the stones I was looking for. Always good quality stones

Posted By Erin in June, 2023

Source: Bizrate

Overall Rating -> 10

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.

Posted By NJD in September, 2023

Source: Bizrate

Overall Rating -> 10

I purchase all of my stones from GemSelect! They're the best I've found for both selection and value.

Posted By Terry in June, 2023

Source: Bizrate

Overall Rating -> 9

making my own jewelry for my birth stone

Posted By LoveGeo in July, 2023

Source: Bizrate

Overall Rating -> 10

Very Good

Posted By Julian in July, 2023

Source: Bizrate

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

Source: Bizrate

Overall Rating -> 10

I bought a small ring green so I may practice my jewelry making.

Posted By HairyOtter in July, 2023

Source: Bizrate

Gemstones A-Z

Buy Octagon Shape 16x12 mm Gems

4.09 ct Oval Spectrolite, 10.1 x 8.3 mm From Finland

1.24 carat Pink Tourmaline, Emerald Cut loose Tourmaline from Mozambique, Natural Untreated Gem, 11.1 x 3.6 mm

0.26 ct Square Cut Kornerupine, 3.7 x 3.6 mm From Sri Lanka

29.7 ct Brown Moonstone, 22.1 x 16.1 mm Oval Cut From India

0.51 carat Blue Sapphire, Diamond-Cut loose Sapphire from Madagascar, Natural Gem, 4.8 mm

13.07 carat Ammolite, loose Certified Ammolite from Canada, Natural Gem, 17.6 x 15.3 mm

2.52 carat Green Tourmaline, Emerald Cut loose Tourmaline from Mozambique, Natural Untreated Gem, 23.8 x 3.6 mm

0.91 carat Pear Shape Peridot, loose Certified Peridot from China, Natural Untreated Gems, 6 x 4.2 mm

11.89 ct Loose Pear Labradorite, 18.2 x 13.2 mm From Madagascar

19.96 carat Pear Jasper, loose Certified Jasper from Indonesia, Natural Untreated Gem, 20.9 x 19.5 mm

9.5 carat Pear Rutile Quartz, loose Certified Rutile Quartz from India, Natural Untreated Gem, 16 x 12.1 mm

2.47 carat Orange Hessonite Garnet, Oval loose Hessonite Garnet from Madagascar, Natural Untreated Gem, 8.9 x 7.6 mm

8.08 ct Oval Cut Strawberry Quartz, 11.9 x 10 mm From Russia

0.92 ct Oval Cut Peridot, 7.1 x 5 mm From China

37.04 ct Drilled Sphere Tiger's Eye Matrix, 10.1 mm From India

0.43 carat Yellow Spessartite Garnet, Oval loose Spessartite Garnet from Mozambique, Natural Untreated Gem, 4.9 x 3.8 mm

16.3 ct Oval Checkerboard Labradorite, 17.7 x 13.2 mm From Madagascar

2.7 carat Orange Hessonite Garnet, Oval loose Hessonite Garnet from Sri Lanka, Natural Untreated Gem, 9.1 x 7.6 mm

1.81 ct Round Cut Strawberry Quartz, 8 mm From Russia

7.02 ct Yellow Quartz, 10.7 x 10.6 mm Carved From Brazil

0.66 carat London Blue Topaz, Square loose Topaz from Brazil, Natural Gem, 5 x 4.8 mm

0.75 carat Green Tourmaline, Baguette Cut loose Tourmaline from Tanzania, Natural Untreated Gem, 7.6 x 3.8 mm

0.44 carat Green Sapphire, Heart loose Sapphire from Tanzania, Natural Gem, 4.6 x 4.6 mm

0.61 carat Green Sapphire, Cushion loose Sapphire from Madagascar, Natural Gem, 6.2 x 4.2 mm

1.92 carat Marquise Cut Amethyst, loose Certified Amethyst from Brazil, Natural Untreated Gem, 12 x 5.9 mm

0.58 ct Loose Blue Green Sapphire, 4.4 x 4.3 mm Cushion Cut From Madagascar

4.26 carat Sky Blue Topaz, Pear Shape loose Topaz from Brazil, Natural Gems, 7 x 5 mm

0.97 ct Marquise Cut Chrysoberyl, 8.9 x 4.8 mm From Sri Lanka

1.39 ct Blue Apatite, 5.1 x 4.1 mm Oval Cut From Madagascar

17.71 ct Loose Oval Lapis Lazuli, 17.1 x 13.4 mm From Afghanistan

3.64 ct Black Star Sapphire, 9.1 x 8.4 mm Oval Cut From Thailand

4.58 ct Fancy Fire Agate, 13.7 x 8.4 mm From Mexico

Gemstone Information

Gemstone SHOP

POLICIES

WHO ARE WE?

Gemstone EDUCATION

WE ARE LOCATED AT