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    LOOSE GEMSTONES

    Natural gemstones weight chart

    Calibrated Size Charts for Gemstones to be set in Standard Jewelry Mountings

    Oval GemstonesOval Cut

    Calibrated Size Chart for Standard Jewelry Mountings (approximate weights)

    Size in mm
    Weight in carat

    5×3 6×4 7×5 8×6 9×7 10×8 11×9 12×10 14×12
    Alexandrite .30 .51 .80 1.45 2.00 3.60 4.25 6.00 8.90
    Amethyst .23 .45 .85 1.25 1.75 2.40 3.20 4.50 6.50
    Aquamarine .20 .40 .75 1.10 1.75 2.25 3.00 4.50 6.75
    Citrine .23 .45 .85 1.25 1.75 2.40 3.25 4.20 5.20
    Diamond .25 .50 .75 1.40 2.00 3.00 4.00 5.00 8.00
    Emerald .25 .52 .85 1.26 1.90 2.60 3.75 5.00 7.50
    Pyrope Garnet .25 .55 1.00 1.40 2.10 2.80 3.75 5.00 7.00
    Iolite .21 .40 .63 1.02 - - - - -
    Opal .16 .28 .47 .78 1.10 1.65 2.15 3.00 4.00
    Peridot .28 .50 .95 1.35 2.00 2.50 3.50 4.00 6.00
    Ruby .35 .60 1.06 1.55 2.20 3.15 3.80 6.00 7.25
    Sapphire .35 .60 1.00 1.55 2.20 3.15 3.80 6.00 7.25
    Tanzanite .20 .48 .89 1.35 - - - - -
    Topaz .28 .57 1.10 1.60 2.50 3.50 4.50 6.00 8.80
    Tourmaline .25 .50 .90 1.18 2.30 2.90 3.50 5.25 6.80
    Tsavorite .28 .52 .75 - - - - - -
    Zircon .40 .75 1.45 2.00 2.85 4.00 5.60 7.50 8.20
    Round GemstonesRound Cut

    Calibrated Size Chart for Standard Jewelry Mountings (approximate weights)

    Size in mm
    Weight in carat

    2 3 4 5 6 6.5 7 8 10
    Alexandrite .04 .12 .35 .63 1.30 1.86 2.15 2.90 5.20
    Amethyst .04 .10 .20 .40 .70 1.10 1.30 1.80 3.30
    Aquamarine .04 .10 .25 .45 .75 1.31 1.60 2.40 3.50
    Citrine .04 .10 .20 .40 .70 1.10 1.30 1.80 3.30
    Diamond .03 .10 .23 .47 .80 1.00 1.25 1.90 3.50
    Emerald .04 .12 .27 .48 .80 1.26 1.70 2.50 6.10
    Pyrope Garnet .05 .13 .30 .60 1.00 1.40 1.60 2.50 5.75
    Opal .02 .09 .16 .34 .57 .75 .83 1.30 2.00
    Peridot .05 .12 .26 .50 .85 1.11 1.25 2.00 5.25
    Ruby .05 .15 .34 .65 1.05 1.41 1.60 2.25 4.50
    Sapphire .05 .15 .34 .65 1.05 1.41 1.60 2.25 4.50
    Topaz .04 .11 .30 .56 1.00 1.36 1.55 2.50 5.75
    Tourmaline .04 .12 .24 .45 .75 1.28 1.55 2.00 3.00
    Zircon .06 .17 .36 .69 1.25 1.58 1.75 2.60 5.00
    Pear GemstonesPear Cut

    Calibrated Size Chart for Standard Jewelry Mountings (approximate weights)

    Size in mm
    Weight in carat

    5×3 6×4 7×5 8×6 9×6 10×7 12×8 14×9
    Alexandrite .30 .50 .85 1.10 2.10 3.60 6.60 8.80
    Amethyst .20 .35 .65 .85 1.25 1.70 4.00 5.00
    Aquamarine .20 .35 .65 .90 1.30 1.85 4.20 5.60
    Citrine .20 .35 .65 .85 1.30 1.70 4.00 5.00
    Diamond .25 .50 .75 1.00 1.50 2.00 3.50 5.00
    Emerald .25 .45 .70 1.05 1.70 2.60 4.15 6.10
    Pyrope Garnet .25 .40 1.00 1.15 1.30 1.80 3.50 5.80
    Opal .13 .22 .35 .50 .70 1.03 1.40 2.45
    Peridot .25 .45 .70 .80 1.10 1.40 3.40 4.75
    Ruby .30 .50 .75 1.00 1.85 2.50 4.75 7.90
    Sapphire .30 .50 .75 1.00 1.85 2.50 4.75 7.90
    Topaz .25 .50 1.00 1.10 2.00 3.50 6.50 8.50
    Tourmaline .35 .45 .60 .90 1.10 1.40 2.80 6.75
    Zircon .30 .70 1.00 1.30 2.60 4.00 5.25 7.50
    Octagon GemstonesOctagon / Emerald Cut

    Calibrated Size Chart for Standard Jewelry Mountings (approximate weights)

    Size in mm
    Weight in carat

    5×3 6×4 7×5 8×6 9×7 10×8 11×9 12×10 14×12
    Alexandrite .40 .70 1.30 2.60 3.60 4.20 6.00 8.50 9.90
    Amethyst .35 .55 1.10 1.60 2.25 2.90 4.20 5.60 7.25
    Aquamarine .25 .50 .80 1.40 2.00 3.00 4.30 4.75 7.75
    Citrine .35 .55 1.00 1.60 2.25 2.90 4.20 5.60 7.25
    Diamond .25 .50 1.00 1.50 3.00 4.00 5.00 7.80 8.80
    Emerald .30 .60 .90 1.80 2.31 3.15 4.50 5.25 5.80
    Pyrope Garnet .40 .80 1.20 1.70 2.50 3.50 4.30 6.35 9.00
    Peridot .35 .60 1.00 1.70 2.25 3.80 5.25 6.25 8.80
    Ruby .55 .75 1.15 1.60 2.30 2.75 4.00 6.25 9.00
    Sapphire .55 .75 1.15 1.75 2.30 2.75 4.00 6.25 9.00
    Topaz .40 .65 1.25 2.40 3.40 4.00 5.75 8.00 9.50
    Tourmaline .30 .60 1.60 2.15 2.80 3.60 4.30 5.20 8.50
    Zircon .60 .85 1.70 2.35 3.90 450 6.20 7.01 8.95
    Marquise GemstonesMarquise Cut

    Calibrated Size Chart for Standard Jewelry Mountings (approximate weights)

    Size in mm
    Weight in carat

    4×2 5×3 6×3 7×3.5 8×4 10×5 12×6 14×7
    Alexandrite .07 .20 .30 .50 .70 1.25 2.10 3.50
    Amethyst .10 .15 .20 .34 .48 .90 1.59 2.45
    Aquamarine .08 .14 .20 .25 .50 .80 1.50 2.75
    Citrine .10 .15 .20 .35 .50 .90 1.59 2.45
    Diamond .12 .18 .25 .37 .50 1.00 2.00 3.00
    Emerald .09 .19 .30 .45 .60 1.40 1.80 2.80
    Pyrope Garnet .09 .16 .25 .42 .60 1.20 2.00 2.85
    Opal .09 .13 .17 .27 .37 .59 1.00 1.25
    Peridot .10 .17 .25 .37 .50 1.00 2.00 2.55
    Ruby .13 .24 .35 .55 .75 1.15 2.20 3.00
    Sapphire .13 .24 .35 .55 .75 1.15 2.20 3.00
    Topaz .07 .17 .30 .50 .70 1.20 2.00 3.40
    Tourmaline .10 .20 .30 .45 .60 .85 1.55 2.20
    Zircon .13 .23 .33 .55 .75 1.25 1.95 3.00