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

1.07 carat Oval Opal, loose Certified Opal from Ethiopia, Natural Untreated Gem, 9.3 x 7 mm

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

1.54 ct Round Cat's Eye Moonstone, 6.9 mm From India

6.61 carat Green Fluorite, Oval loose Fluorite from India, Natural Untreated Gem, 12 x 9.3 mm

0.73 carat Emerald Cut Emerald, loose Certified Emerald from Colombia, Natural Gem, 6 x 3.9 mm

1.28 ct Blue Apatite, 4.9 x 4 mm Oval Cut From Madagascar

5.35 ct Fancy Fire Agate, 16 x 11.7 mm From Mexico

2.27 carat Orange Hessonite Garnet, Oval loose Hessonite Garnet from Madagascar, Natural Untreated Gem, 8.8 x 7.2 mm

13.29 carat Oval Amethyst, loose Certified Amethyst from Brazil, Natural Untreated Gems, 13.9 x 9.9 mm

25.32 carat Ammolite, loose Certified Ammolite from Canada, Natural Gem, 28.1 x 20.2 mm

2.21 ct Yellow Andesine Labradorite, 10.1 x 8.1 mm Oval Cut From Congo

5.72 carat Swiss Blue Topaz, Carved Flower loose Topaz from Brazil, Natural Gem, 12.4 x 8.9 mm

9 ct Carved Prehnite, 18.4 x 13 mm From South Africa

20.76 carat Pear Dendritic Agate, loose Certified Dendritic Agate from India, Natural Untreated Gem, 23.9 x 19.9 mm

8.04 carat Pink Morganite, Pear loose Morganite from Afghanistan, Natural Untreated Gem, 19.7 x 11.8 mm

0.57 carat Pink Sapphire, Pear Shape loose Sapphire from Madagascar, Natural Gem, 5.9 x 5.1 mm

2.5 carat Marquise Cut Pyrope Garnet, loose Certified Pyrope Garnet from Mozambique, Natural Untreated Gems, 10 x 5.1 mm

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

5.61 ct Yellow Quartz, 14.4 x 10.7 mm Carved From Brazil

2.96 ct Round Rutile Quartz, 7.2 mm From India

0.37 ct Loose Pink Sapphire, 4.9 x 4 mm Oval Cut From Madagascar

8.16 carat Swiss Blue Topaz, Marquise-Cut loose Topaz from Brazil, Natural Gems, 14 x 7.9 mm

2.33 carat London Blue Topaz, Round loose Topaz from Brazil, Natural Gem, 8 mm

2.18 ct Oval Spectrolite, 10.1 x 8.3 mm From Finland

0.43 carat Green Sapphire, Trillion-Cut loose Sapphire from Madagascar, Natural Gem, 4.4 x 4.3 mm

0.83 carat Pink Morganite, Pear Shape loose Morganite from Afghanistan, Natural Untreated Gem, 7 x 5.4 mm

2.28 ct Orange Moonstone, 9.1 x 7.1 mm Cushion Cut From India

1.34 ct Loose Oval Cut Black Opal, 9.7 x 7.4 mm From Ethiopia

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

2.5 carat Brown Tourmaline, Pear Shape loose Tourmaline from Mozambique, Natural Untreated Gems, 6.4 x 4.5 mm

37.71 ct Oval Malachite, 30.5 x 20.3 mm From Congo

5.76 ct Oval Black Opal, 15.4 x 11.9 mm From Ethiopia

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