Free Gemstone Identifier by Photo —
What Gemstone Is This?

How to Identify Gemstones — What the AI Looks For

When you upload a photo to our free gemstone identifier, the AI analyses the same visual properties a gemologist would examine. Understanding these properties helps you take better photos and interpret your results more confidently.

Colour

Colour is often the first clue but rarely definitive on its own — many gems share similar hues. The AI assesses hue, tone, and saturation, and looks for colour zoning (uneven colour distribution) which can indicate natural origin or treatment. Some gems show pleochroism (different colours from different angles) — mention this in your notes if observed.

Cut Style

Brilliant cuts (round, oval, pear) have triangular and kite-shaped facets designed to maximise sparkle — common for diamond, sapphire, and topaz. Step cuts (emerald cut, baguette) have parallel rectangular facets that showcase colour and clarity — classic for emerald and aquamarine. Cabochons are smooth domes without facets — used for opal, turquoise, moonstone, and cat’s eye stones. Cut style narrows the possibilities considerably.

Transparency and Clarity

Gemstones range from transparent (light passes clearly) to translucent to opaque. Inclusions visible in photos — needles, feathers, crystals, colour bands — help identify species and assess natural vs synthetic origin. Glass simulants often show round bubbles; natural gems show angular mineral inclusions.

Luster and Surface

Luster describes how light reflects from the surface: adamantine (diamond-like brilliance), vitreous (glassy), pearly, silky, or waxy. Surface wear, scratches, and chip patterns on older jewellery stones provide context about age and hardness. A vitreous luster with surface scratches suggests a softer gem like opal or turquoise.

Gemstone Identification Tests You Can Do at Home

While our AI works from photos alone, these simple tests improve accuracy when you add results in the notes field.

The Scratch Test (Mohs Hardness)

Your fingernail is Mohs 2.5, a copper coin is Mohs 3.5, a steel knife is Mohs 5.5, and glass is Mohs 5.5–6. Diamond is Mohs 10; sapphire and ruby Mohs 9; emerald Mohs 7.5–8; opal Mohs 5.5–6.5. Knowing whether your stone scratches glass immediately eliminates many possibilities.

The Magnet Test

Most gemstones are non-magnetic. Strong magnetic attraction suggests iron-bearing minerals or imitations, not precious gems. Garnet (almandine) can show weak attraction. Magnetic response rules out diamond, sapphire, ruby, and emerald.

UV Fluorescence

Many gems fluoresce under UV light. Diamond often fluoresces blue; ruby red; opal white or green; some sapphires red or orange. Fluorescence patterns help distinguish natural from synthetic stones but require a UV torch to observe. Mention any UV response in your notes.

Common Gemstone Confusions

These are the mix-ups we see most often. Understanding them helps you interpret your result:

• Blue sapphire vs blue topaz — topaz is lighter, often brighter blue; sapphire is deeper with silk inclusions. Use our aquamarine vs blue topaz and sapphire tools.
• Emerald vs green glass — glass has round bubbles and uniform colour; emerald shows natural inclusions (jardin). Use our emerald identifier.
• Ruby vs red spinel vs garnet — ruby is deep red with silk; spinel is often cleaner; garnet shows different inclusions. Use our ruby identifier and garnet identifier.
• Citrine vs heated amethyst — most commercial citrine is heat-treated amethyst. Natural citrine is rare. Use our citrine identifier.
• Opal vs synthetic opal — synthetic opal shows uniform columnar colour pattern; natural opal has irregular play of colour. Use our opal identifier.
• Diamond vs cubic zirconia — CZ shows excessive fire and rounded facet edges. Use our diamond identifier.

Understanding Gemstone Treatments

Most gemstones on the market have been treated to improve appearance. Our AI flags likely treatments when visual clues are visible, but cannot confirm treatment status from photos alone. Common treatments include:

• Heat treatment — improves colour in ruby, sapphire, aquamarine, tanzanite, and citrine (from amethyst)
• Oiling / resin filling — conceals fractures in emerald, ruby, and turquoise
• Irradiation — produces blue topaz and some coloured diamonds
• Dyeing — enhances colour in jade, turquoise, chalcedony, and howlite
• Diffusion — adds colour to sapphire surface layers
• Fracture filling — glass or lead-glass filling in diamond and ruby

Using Our Specialist Identifier Tools

The general gemstone identifier works for any stone. If you already suspect what you have, our specialist tools give more targeted results: diamond, ruby, sapphire, emerald, opal, jade, turquoise, and 20+ more. For rough mineral specimens, try our crystal identifier or mineral identifier.