Weight Chart

Any and all weight charts are only guides for estimated weights. The reason for this is the way that a gemstone is cut has a lot to do with the weight of the stone. Crowns or pavilions that are heavy or light, thick or thin girdles all are determining factors on weight. Weight by the formula method works well if you know the specific gravity of the gemstone in question, but this method is also limited by the same factors of make. The best method, is to weigh the stone with a scale designed to weigh gemstones.

Rounds	2mm	3mm	4mm	5mm	6mm	7mm	8mm	10mm
Alexandrite	0.04	0.12	0.35	0.63	1.30	2.15	2.90	5.20
Amethyst	0.04	0.10	0.20	0.40	0.70	1.30	1.80	3.30
Aqua	0.04	0.10	0.25	0.45	0.75	1.60	2.40	3.50
Citrine	0.04	0.10	0.20	0.40	0.70	1.30	1.80	3.30
Diamond	0.04	0.10	0.23	0.47	0.85	1.25	1.90	4.25
Emerald	0.04	0.12	0.27	0.48	0.80	1.70	2.50	6.10
Garnet	0.05	0.13	0.30	0.60	1.00	1.60	2.50	5.75
Opal	0.02	0.09	0.16	0.34	0.57	0.83	1.30	2.00
Peridot	0.05	0.12	0.26	0.50	0.85	1.25	2.00	5.25
Ruby	0.05	0.15	0.34	0.65	1.05	1.60	2.25	4.50
Sapphire	0.05	0.15	0.34	0.65	1.05	1.60	2.25	4.50
Topaz	0.04	0.11	0.30	0.56	1.00	1.55	2.50	5.75
Tourmaline	0.04	0.12	0.24	0.45	0.75	1.55	2.00	3.00
Zircon	0.06	0.17	0.36	0.69	1.25	1.75	2.60	5.00

OVAL	5X3mm	6x4mm	7x5mm	8x6mm	9x7mm	10x8mm	12x10	16x12	18x13	20x15
Alexandrite	0.30	0.60	0.80	1.45	2.00	3.60	6.00	12.50	18.00	24.00
Amethyst	0.23	0.45	0.85	1.25	1.75	2.40	4.50	11.00	14.00	16.00
Aqua	0.20	0.40	0.75	1.10	1.75	2.25	4.50	10.15	10.50	14.50
Citrine	0.23	0.45	0.85	1.25	1.75	2.40	4.20	9.00	10.50	20.00
Diamond	0.25	0.50	0.75	1.40	2.00	3.00	5.00	11.50	16.00	21.50
Emerald	0.28	0.52	0.85	1.26	1.90	2.60	5.00	12.00	14.50	18.00
Garnet	0.25	0.55	1.00	1.40	2.10	2.80	5.00	10.00	13.25	20.00
Opal	0.16	0.28	0.47	0.78	1.10	1.65	3.00	5.25	5.75	9.90
Peridot	0.28	0.50	0.95	1.35	2.00	2.50	4.00	9.50	13.00	20.00
Ruby	0.35	0.60	1.00	1.55	2.20	3.15	6.00	12.00	13.00	20.00
Sapphire	0.35	0.60	1.00	1.55	2.20	3.15	6.00	12.00	13.00	20.00
Topaz	0.27	0.57	1.10	1.60	2.50	3.50	6.00	12.00	17.00	22.00
Tourmaline	0.25	0.50	0.90	1.18	2.30	2.90	5.25	8.50	12.00	18.00
Zircon	0.40	0.75	1.45	2.00	2.85	4.00	7.50	13.50	14.50	23.00

EMERALD	5X3mm	6x4mm	7x5mm	8x6mm	9x7mm	10x8mm	12x10	16x12	18x13	20x15
Alexandrite	0.40	0.70	1.30	2.60	3.60	4.20	8.50	14.50	22.00	27.00
Amethyst	0.35	0.55	1.00	1.60	2.25	2.90	5.60	13.00	17.00	22.00
Aqua	0.25	0.50	0.80	1.40	2.00	3.00	4.75	13.50	17.00	22.00
Citrine	0.35	0.55	1.00	1.60	2.25	2.90	5.60	13.00	17.00	22.00
Diamond	0.25	0.50	1.00	1.50	3.00	4.00	7.80	13.00	20.00	25.50
Emerald	0.30	0.60	0.90	1.80	2.31	3.15	5.25	14.00	17.50	22.50
Garnet	0.40	0.80	1.20	1.70	2.50	3.50	6.35	17.50	21.00	27.00
Peridot	0.35	0.60	1.00	1.70	2.25	3.80	6.25	17.00	20.00	26.00
Ruby	0.55	0.75	1.15	1.60	2.30	2.75	6.25	12.50	18.50	27.00
Sapphire	0.55	0.75	1.15	1.75	2.30	2.75	6.25	12.50	18.50	27.00
Topaz	0.40	0.65	1.25	2.40	3.40	4.00	8.00	14.00	21.00	26.00
Tourmaline	0.30	0.60	1.60	2.15	2.80	3.60	5.20	13.00	16.50	25.00
Zircon	0.60	0.85	1.70	2.35	3.90	4.50	7.00	14.30	19.90	28.70

PEAR	5X3mm	6x4mm	8x5mm	9x6mm	10x7mm	13x8mm	14x10m
Alexandrite	0.30	0.50	1.10	2.10	3.60	6.60	8.80
Amethyst	0.20	0.35	0.85	1.25	1.70	4.00	5.00
Aqua	0.20	0.35	0.90	1.30	1.85	4.20	5.60
Citrine	0.20	0.35	0.85	1.30	1.70	4.00	5.00
Diamond	0.25	0.50	1.00	1.50	2.00	3.50	5.00
Emerald	0.25	0.45	1.05	1.70	2.60	4.15	6.10
Garnet	0.25	0.40	1.15	1.30	1.80	3.50	5.80
Opal	0.13	0.22	0.50	0.70	1.00	1.40	2.45
Peridot	0.25	0.45	0.80	1.10	1.40	3.40	4.75
Ruby	0.30	0.50	1.00	1.85	2.50	4.75	7.90
Sapphire	0.30	0.50	1.00	1.85	2.50	4.75	7.90
Topaz	0.25	0.50	1.10	2.00	3.50	6.50	8.50
Tourmaline	0.35	0.45	0.90	1.10	1.40	2.80	6.75
Zircon	0.30	0.70	1.30	2.60	4.00	5.25	7.50

MARQUIS	4x2mm	6x3mm	8x4mm	10x5mm	12x6mm	14x7mm
Alexandrite	0.07	0.30	0.70	1.25	2.10	3.50
Amethyst	0.10	0.20	0.48	0.90	1.59	2.45
Aqua	0.08	0.20	0.50	0.80	1.50	2.75
Citrine	0.10	0.20	0.50	0.90	1.59	2.45
Diamond	0.12	0.25	0.50	1.00	2.00	3.00
Emerald	0.09	0.30	0.60	1.40	1.80	2.80
Garnet	0.09	0.25	0.60	1.20	2.00	2.85
Opal	0.09	0.17	0.37	0.59	1.00	1.25
Peridot	0.10	0.25	0.50	1.00	2.00	2.55
Ruby	0.13	0.35	0.75	1.15	2.20	3.00
Sapphire	0.13	0.35	0.75	1.15	2.20	3.00
Topaz	0.07	0.30	0.70	1.20	2.00	3.40
Tourmaline	0.10	0.30	0.60	0.85	1.55	2.20
Zircon	0.13	0.33	0.75	1.25	1.95	3.00

IMPORTANT

The weights in the following charts are based on the stones shape and size and are estimates only. The weights will very for shape and size due to the proportions of the stone (girdle thickness, depth, style of cut, etc.) The following weight formulas will give a better weight estimate for specific stones.

ROUNDS: diameter x diameter x depth x S. G. x .0018 = ct. weight

OVAL: length + width x length + width x depth x S.G. x.0025 = ct. weight

2 2

EMERALD: length x width x depth x S.G. x .0026 = ct. weight

RECTANGLE: length x width x depth x S.G. x .0026 = ct. weight

SQUARE: length x width x depth x S.G. x .0023 = ct. weight

MARQUIS: length x width x depth x S.G. x .0016 = ct. weight

PEAR: length x width x depth x S.G. x .0018 = ct. weight

HEART: length x width x depth x S.G. x .0021 = ct. weight

TRILLION: length x width x depth x S.G. x .0018 = ct. weight

CABOCHON: length x width x depth x S.G. x .0026