Gemstone Tools

Free interactive tools to help you compare, identify, calculate, and learn about gemstones.

⚖️ converter

Carat Weight Converter

Convert between carats, grams, milligrams, ounces troy, and points. Calculate price per carat instantly.

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💎 comparison

Gem Comparator

Compare two gemstones side by side — hardness, price, color, refractive index, and more.

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📊 comparison

Gem Property Ranker

Rank all gemstones by any property — hardness, price, refractive index, specific gravity, or dispersion.

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⚖️ calculator

Carat Weight Converter

Convert between carats, grams, milligrams, points, and grains. 1 carat = 0.2 grams = 200 mg = 100 points.

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💰 calculator

Gemstone Price Estimator

Estimate gemstone price range based on type, carat weight, and quality grade.

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💍 calculator

Ring Size Converter

Convert ring sizes between US, UK, EU, and Japanese standards with inner diameter in mm.

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✨ calculator

Brilliance & Fire Calculator

Calculate a gemstone's brilliance score from refractive index and fire score from dispersion value.

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🧪 calculator

Specific Gravity Tester

Calculate specific gravity from weight in air and weight in water. Match results to known gemstones.

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📏 calculator

Gem Dimensions Estimator

Estimate carat weight from gemstone dimensions (L x W x D) using industry shape factors and specific gravity.

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🎂 finder

Birthstone Finder

Find your birthstone by month — modern, traditional, and alternative options with properties.

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🔍 finder

Gem Identifier

Identify a gemstone by its color, hardness range, and luster. Get a ranked list of matching candidates.

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🎨 finder

Gem Color Matcher

Find gemstones that match a specific color. Browse all gems available in your chosen color.

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♈ finder

Zodiac Stone Finder

Find gemstones associated with your zodiac sign — traditional and modern correspondences.

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💐 finder

Anniversary Stone Finder

Find the traditional and modern gemstone for each wedding anniversary year, from 1st to 60th.

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💪 reference

Interactive Mohs Scale

Explore the Mohs hardness scale with real gemstone examples at each level. See which gems are harder than others.

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🔮 reference

Crystal System Explorer

Learn about the 7 crystal systems and see which gemstones belong to each — cubic, hexagonal, trigonal, and more.

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🌈 reference

Refractive Index Lookup

Look up refractive index values for any gemstone. Sort and filter the complete RI table.

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🛡️ reference

Durability Checker

Check if a gemstone is suitable for rings, daily wear, or delicate jewelry based on hardness, toughness, and stability.

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🔬 reference

Treatment Guide

Learn about common gemstone treatments — heat, oiling, irradiation, coating — and how they affect value.

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💎 advisor

Setting Advisor

Get setting recommendations based on your gemstone's hardness, cleavage, and intended use (ring, pendant, earrings).

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🧼 advisor

Care Advisor

Get personalized care instructions for any gemstone — cleaning methods, storage tips, and what to avoid.

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