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

0.44 ct Blue Kyanite, 3.7 mm Round Cut From Nepal

38.56 ct Green Jadeite, 28.3 x 22.2 mm Oval Cut From Myanmar

1.16 carat Heart Pyrope Garnet, loose Certified Pyrope Garnet from Mozambique, Natural Untreated Gems, 5 x 4.9 mm

3.49 carat Oval Opal, loose Certified Opal from Australia, Natural Untreated Gem, 11 x 9.2 mm

26.56 ct Oval Rainbow Moonstone, 24.5 x 17.6 mm From the United States

2.46 ct Brown Moonstone, 11.2 x 10.8 mm Carved From India

0.78 carat Oval Emerald, loose Certified Emerald from Colombia, Natural Gem, 5.6 x 4.5 mm

7.46 ct Green Agate, 12.6 x 11.5 mm Oval Cut From India

4.04 carat White Zircon, Diamond-Cut loose Zircon from Cambodia, Natural Gems, 7.3 mm

15.82 ct Loose Oval Lapis Lazuli, 16.3 x 12.3 mm From Afghanistan

3.29 carat Oval Amethyst, loose Certified Amethyst from Brazil, Natural Untreated Gem, 10.1 x 8.2 mm

2.47 ct Round Cut Strawberry Quartz, 7.1 mm From Russia

1.98 carat Orange Zircon, Oval loose Zircon from Tanzania, Natural Untreated Gem, 8.1 x 6.1 mm

6.89 ct Oval Agate, 12.5 x 11.6 mm From Indonesia

3.96 ct Oval Cut Rainbow Moonstone, 9.2 x 7.1 mm From the United States

20.39 ct Gray Jadeite, 19.1 x 17.7 mm Oval Cut From Myanmar

1.34 carat Green Tourmaline, Emerald Cut loose Tourmaline from Mozambique, Natural Untreated Gem, 23.1 x 2.7 mm

23.89 ct Cushion Howlite, 26.9 x 17.6 mm From the United States

1.54 ct Loose Oval Cut Black Opal, 10.2 x 8 mm From Ethiopia

0.31 ct Yellow Diamond, 4.2 mm Diamond Cut From India

2.21 ct Cushion Cut Peridot, 7.8 x 7.3 mm From Myanmar

0.37 ct Loose Orange Sapphire, 4.8 x 2.5 mm Marquise Cut From Tanzania

7.32 ct Oval Quartz Cat's Eye, 12.8 x 10.2 mm From Sri Lanka

1.98 carat Orange Hessonite Garnet, Emerald Cut loose Hessonite Garnet from Sri Lanka, Natural Untreated Gem, 7.8 x 5.9 mm

33.23 ct Oval Hematite, 21.7 x 17.4 mm From Brazil

37.31 ct Baguette Tiger's Eye Matrix, 28.2 x 24.2 mm From Mexico

1.68 carat Oval Opal, loose Certified Opal from Ethiopia, Natural Untreated Gems, 6.7 x 5 mm

4.09 carat Oval Strawberry Quartz, loose Certified from India, Natural Untreated Gem, 12.1 x 9.9 mm

0.52 ct Pink Spinel, 4.6 x 4.2 mm Cushion Cut From Tanzania

0.64 carat Round Grossularite Garnet, loose Certified Grossularite Garnet from Tanzania, Natural Untreated Gem, 4.9 mm

0.25 ct Baguette Cut Iolite, 5 x 3 mm From Madagascar

4.03 carat Yellow Citrine, Oval loose Citrine from Brazil, Natural Untreated Gem, 12.6 x 9.3 mm

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