Calibrated Marquise Cut Gemstones in Size 12x6 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 marquise shaped facet cut gems, gemstone carvings and cabochons available in 12 mm x 6 mm sizes. For the largest selection of colored gemstones, Shop GemSelect Online.

As a general guideline, when it comes to calibrated gems, they are not usually expected to be cut to exact measurements and specifications. But rather, they're cut with slight variance in size, though the close approximatation in size is not clearly defined, there are general guidelines for what is considered acceptable. Obviously larger and heavy carat weight stones allow more room in size for variance, while smaller stones may leave little to none. This means a large 30mm calibrated gemstone, could actually be closer to 31 millimeters. For this reason, we recommend to always view the exact size in addition to the calibrated size details. The exact size will inform you of the variance you can expect. Some setting styles are more flexible with variance, such as prong settings, while other styles of mountings may need almost an exact size to the fraction of millimeter.

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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Gemstones A-Z

Buy Marquise Shape 12x6 mm Gems

0.58 carat Blue Tanzanite, Pear Shape loose Tanzanite from Tanzania, Natural Gems, 5.1 x 3.9 mm

3.06 ct Round Strawberry Quartz, 8.2 mm From Brazil

4.36 carat White Zircon, Oval loose Zircon from Cambodia, Natural Gems, 6 x 4.1 mm

5.64 carat Pink Kunzite, Pear Shape loose Kunzite from Afghanistan, Natural Untreated Gem, 13.7 x 8.3 mm

2.78 carat Pear Shape Tsavorite Garnet, loose Certified Tsavorite Garnet from Tanzania, Natural Untreated Gems, 4.1 x 3 mm

6.6 ct Diamond Cut Smoky Quartz, 12.5 mm From Brazil

26.89 ct Oval Jasper, 31.9 x 23.5 mm From Indonesia

4.89 carat Marquise Cut Pyrope Garnet, loose Certified Pyrope Garnet from Mozambique, Natural Untreated Gems, 9.9 x 5 mm

2.58 ct Orange Moonstone, 8.1 x 6.1 mm Cushion Cut From India

29.55 ct Oval Rose Quartz, 21.8 x 16.7 mm From South Africa

4.91 ct Orange Sunstone, 10 x 8 mm Oval Cut From India

0.92 ct Pink Morganite, 6.9 x 5.8 mm Oval Cut From Afghanistan

0.42 carat Yellow Citrine, Oval loose Citrine from Brazil, Natural Untreated Gem, 6 x 4.1 mm

0.78 ct Octagon Cut Color-Change Diaspore, 6.6 x 4.8 mm From Turkey

2.71 ct Oval Sillimanite Cat's Eye, 7.6 x 5.6 mm From Madagascar

6.56 ct Yellow Quartz, 12 x 12 mm Carved From Brazil

17.72 ct Loose Cushion Charoite, 21.4 x 15.1 mm From Russia

3.83 ct Round Checkerboard Smoky Quartz, 8 mm From Brazil

11.71 carat Swiss Blue Topaz, Ball loose Topaz from Brazil, Natural Gems, 8.4 mm

10.96 carat Black Tourmaline, Emerald Cut loose Tourmaline from Mozambique, Natural Untreated Gem, 16.6 x 9.3 mm

1.57 carat Emerald Cut Amethyst, loose Certified Amethyst from Brazil, Natural Untreated Gem, 7.2 x 7.2 mm

11.73 ct Blue Green Turquoise, 24.9 x 16.1 mm Oval Cut From China

2.91 ct Oval Cat's Eye Opal, 11.4 x 8 mm From Madagascar

9.44 carat Pear Maw-Sit-Sit, loose Certified Maw-Sit-Sit from Myanmar, Natural Untreated Gem, 15.3 x 11.4 mm

8.83 carat Oval Star Garnet, loose Certified Star Garnet from India, Natural Untreated Gem, 12.8 x 9.6 mm

11.92 carat Pear Seraphinite, loose Certified Seraphinite from Russia, Natural Untreated Gems, 14.2 x 10 mm

2.42 carat Oval Amethyst, loose Certified Amethyst from Brazil, Natural Untreated Gems, 6 x 4.2 mm

35.54 ct Carved Labradorite, 31.5 x 21.3 mm From Madagascar

13.44 carat Pear Obsidian, loose Certified Obsidian from the United States, Natural Untreated Gem, 22.8 x 14 mm

0.55 ct Loose Orange Sapphire, 4.5 x 4.5 mm Cushion Cut From Tanzania

0.13 ct Square Cut Iolite, 3 x 2.9 mm From Madagascar

1.2 carat Oval Opal, loose Certified Opal from Australia, Natural Untreated Gem, 10.1 x 8 mm

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