Rock Identifier — What Rock Is This?
Found a rock and want to know what it is? Upload a photo for a free identification with an honest confidence score, likely look-alikes, and the simple field tests that confirm it. Built to admit when a specimen is ambiguous instead of guessing.
How to photograph a rock for identification
- • Show a freshly broken or cut surface if you can — weathered outer crust hides the real texture and color.
- • Include something for scale, and capture the grain: are the crystals visible, or is it smooth and fine-grained?
- • Use daylight and avoid wetting the rock unless you note it (water deepens color and sheen).
- • A second photo of a different face often helps with layered or banded rocks.
The three rock families — and where yours fits
Almost every rock belongs to one of three families, and naming the family first narrows the answer fast. The identifier weighs texture, grain and structure to place your specimen, then names the specific rock:
- Igneous — cooled from molten rock, with interlocking crystals or a glassy texture. Coarse and speckled like granite, fine and dark like basalt, or glassy like obsidian.
- Sedimentary — built in layers from grains, mud or shells. Gritty like sandstone, fine and fizzing in acid like limestone, or a jumble of cemented pebbles like conglomerate.
- Metamorphic — older rock reworked by heat and pressure, often banded or sheeny. Striped like gneiss, flaky like schist, or recrystallized like marble and quartzite.
Three quick tests to confirm a rock
- Acid fizz: a drop of vinegar that fizzes signals a carbonate rock like limestone or marble.
- Hardness: can it be scratched by a steel knife (≈5.5)? Soft, scratchable rocks rule out hard quartz-rich ones.
- Texture & layers: interlocking crystals point to igneous; visible layers or grains to sedimentary; banding or sheen to metamorphic.
Frequently asked questions
What kind of rock is this?
Upload a photo and the identifier will name the most likely rock and its family — igneous, sedimentary or metamorphic. Rocks are mixtures of minerals, so texture and grain size matter as much as color; the tool weighs all of these and tells you how confident it is.
How do I tell igneous, sedimentary and metamorphic rocks apart?
Igneous rocks (granite, basalt) form from cooled magma and have interlocking crystals or a glassy/bubbly texture. Sedimentary rocks (sandstone, limestone) form in layers and often contain grains or fossils. Metamorphic rocks (gneiss, schist, marble) show banding, foliation or a sugary recrystallized texture.
Is it a rock or a mineral?
A mineral is a single chemical compound (quartz, pyrite); a rock is a naturally occurring mix of one or more minerals (granite is quartz + feldspar + mica). If you see many different grains, it's likely a rock — if it's one uniform substance or crystal, it's probably a mineral.
Is the rock identifier free?
Yes — your first 3 identifications are free. Pro covers 100 identifications a day (600 a month), plus value, authenticity and care reports.
How accurate is it with rocks?
Rocks are mixtures, not single crystals, so a photo alone is harder to read than a clean gemstone — two grey rocks can look identical yet belong to different families. That is why the identifier returns a confidence score and likely look-alikes rather than one forced guess, and points you to the field test that settles it. For a common, well-lit specimen it is usually right about the rock or at least its family; for a weathered or ambiguous piece it will say so plainly, and the quick tests above do the rest. See our rock identification guide for the full walkthrough.
Think it might be a crystal or gemstone instead? Try the crystal identifier