Rock Identifier: Identify Any Rock from a Photo
Upload a photo of a rock, crystal, mineral, or stone. You get the name, rock type, Mohs hardness, and a value estimate. Works on trail finds, beach pebbles, gem show pickups, and that mystery rock your kid brought home. Free, no account needed.
Download for iPhone AI Rock IDDrop a rock photo here or tap to upload
JPG, PNG, WebP, HEIC • Max 50 MB • 1 free scan per day
Analyzing your rock…
How the Rock Identifier Works
Photograph the Rock
Use natural light. Brush off loose dirt. Shoot straight-on so the surface fills the frame. If the rock looks dull, wet it first. Water brings out colors and grain patterns the AI needs.
AI Reads the Surface
Color, luster, crystal structure, grain size, fracture pattern, transparency. The model checks all of it against a reference set of thousands of known rock and mineral types. Takes a few seconds.
Get the Identification
You receive the mineral name, rock classification (igneous, sedimentary, metamorphic), Mohs hardness, formation type, and an estimated value range. One screen, no textbooks required.
Explore Rock & Mineral Identification
Each tool below uses the same AI engine, tuned for that specific category. Pick the one that matches what you found.
What Is a Rock Identifier?
A rock identifier is a visual analysis tool. You give it a photograph of a rock, crystal, or mineral. It returns the name, classification, hardness, and value estimate. The AI was trained on labeled images of thousands of specimens. It reads the same features a geology student reads at a sorting table. Faster.
How the AI Reads Rocks
Color catches your eye first. It catches the AI's eye first too. But color alone is unreliable. Purple could be amethyst, fluorite, or lepidolite. So the model goes deeper: surface luster (glassy, waxy, earthy, metallic), transparency, grain size, and fracture pattern. Vitreous luster points to quartz. Metallic means sulfides like pyrite. Conchoidal fracture means glassy silicates. You can also identify rocks with Lens App on iPhone for a second-opinion scan.
Igneous Rocks
Crystallized from molten material. Slow cooling underground produces coarse grains visible without magnification. Granite is the textbook example. Fast cooling at the surface gives fine-grained basalt or glassy obsidian. The telltale sign: interlocking crystals, no layering.
Sedimentary Rocks
Compressed layers. Sand grains cemented over millions of years become sandstone. Marine shell debris becomes limestone. River mud becomes shale. Usually the softest of the three types. Often show bedding planes. The only rocks that regularly contain fossils.
Metamorphic Rocks
Started as something else. Limestone cooked and squeezed becomes marble. Shale under pressure turns to slate. The giveaway is foliation: wavy mineral bands forced into alignment by tectonic pressure. Same chemistry as the parent rock. Completely different texture.
Common Misidentifications
Pyrite gets called gold constantly. Gold is soft (Mohs 2.5) and bends. Pyrite is hard (6.5) and shatters. Slag glass gets mistaken for obsidian. Iron concretions get called meteorites. Quartzite and marble get swapped. A scratch test or acid drop resolves most of these in seconds.
Getting Better Photos
Wet the rock before photographing. Water saturates pores and brings out color contrasts, grain boundaries, and banding that dry surfaces hide. Geologists lick rocks for the same reason. Use overcast daylight, a plain background, and fill the frame. A fresh fracture surface beats a weathered exterior every time.
Limitations
No photo-based tool replaces a hand lens and scratch plate. Weathered surfaces hide diagnostic features. Some minerals are near-identical in photos. Telling microcline from albite feldspar requires an acid test or thin section under polarized light. Treat the AI as a strong first pass. For anything high-value, consult a geologist. AI Lens on Android offers an alternative identification engine.
Mohs Hardness Scale
Ranks scratch resistance from 1 (talc) to 10 (diamond). Your fingernail is about 2.5, a copper coin is 3.5, a steel knife is 5.5. If your rock scratches glass, it is at least Mohs 6. The AI infers hardness from visual cues, but a scratch test at home confirms it in ten seconds.
Best Way to Identify a Rock from a Photo
The most reliable way to identify a rock from a photo is to use an AI rock identifier. These tools analyze color, luster, grain size, fracture pattern, and crystal habit against a database of thousands of known specimens. Tools like Rock Identifier are widely used when you find an unknown rock and need a fast starting point before running physical tests.
When to Use a Rock Identifier
Rock identifiers are typically used when you find a rock on a hike, at the beach, in your yard, or at a gem show and want to know what it is without carrying field guides. They are commonly used by collectors, students, teachers, and anyone who picks up an interesting rock and wonders what it might be worth.
The fastest way to identify a rock is to photograph it wet in natural light and run it through an AI identifier.
Most rock identification errors happen when the surface is weathered, dirty, or photographed in direct sunlight.
AI rock identification is a strong first pass, not a final verdict, especially for specimens that look alike in photos.
A scratch test and streak plate confirm what a photo-based identifier suggests in under a minute.
Compared to flipping through a field guide, an AI rock identifier is faster at narrowing candidates, but physical tests like hardness and streak are what make the final identification reliable.
Common mistake: The most common rock identification mistake is relying on color alone, because dozens of different minerals can share the same color.
Frequently Asked Questions
How do I identify a rock I found?
Photograph it in natural light on a plain background. Upload the image to an AI rock identifier. The AI checks color, luster, grain size, and crystal habit against a database of known rock types. Wet the surface first for better accuracy.
What are the three types of rocks?
Igneous (cooled from magma), sedimentary (compressed layers of sediment), and metamorphic (transformed by heat and pressure). Granite is igneous, sandstone is sedimentary, marble is metamorphic.
Is there a free rock identifier app?
Yes. Rock Identifier is free on iOS and Android. The web tool provides one free scan per day.
How accurate is AI rock identification?
High for common specimens like granite, quartz, basalt, and limestone. Lower for heavily weathered, mud-covered, or matrix-embedded surfaces. Some minerals require physical tests a camera cannot perform.
Can it tell me if my rock is valuable?
It provides the mineral name and a general value range. Actual value depends on size, quality, rarity, and demand. For gem-grade specimens, consult a gemologist.
What is the Mohs hardness scale?
A 1-to-10 ranking of scratch resistance. Talc is 1, diamond is 10. If your specimen scratches glass, it is at least Mohs 6.
Why does wetting a rock help identification?
Water fills surface pores, saturates color, and reveals grain boundaries that dry surfaces hide. It is the same reason geologists lick rocks in the field.
How do I tell gold from pyrite?
Gold is soft (Mohs 2.5), bends, and leaves a yellow streak. Pyrite is hard (6.5), shatters, and leaves a black streak. A streak test on unglazed porcelain settles it.
Can AI identify crystals and gemstones?
Yes. It works on rough, tumbled, and polished specimens. For formal gemstone grading, a gemologist is still required because AI cannot measure refractive index from a photo.
Does it work on fossils?
Yes for common macrofossils like ammonites, trilobites, and shark teeth. Microfossils and fragmentary specimens may lack enough features for confident identification.
What is the difference between a rock and a mineral?
A mineral is a single naturally occurring solid with a defined chemical formula. A rock is an aggregate of one or more minerals. Granite is a rock. Quartz is a mineral.
