What Kind of Rock Is This?
Found a rock and want to know what it is? Upload a photo and our identifier names the most likely rock in seconds, tells you how confident it is, and shows you the simple tests to confirm it — no confidently-wrong guesses.
The three families of rock
Almost every rock falls into one of three groups — placing yours is the first step:
- Igneous — cooled from molten rock; interlocking crystals or a glassy/bubbly texture. Granite, basalt, obsidian, pumice.
- Sedimentary — compacted grains or layers, often with fossils. Sandstone, limestone, shale, conglomerate.
- Metamorphic — reshaped by heat and pressure, often banded or foliated. Gneiss, schist, slate, marble, quartzite.
Want the full method? Read the rock identification guide.
How to photograph it for the best result
- Shoot in daylight against a plain background, filling the frame with the rock.
- Show a freshly broken or cut surface if you can — weathered outsides hide the real colour and grain.
- Include something for scale, and capture any layers, grains or crystals up close.
How to confirm what you found
A photo gets you most of the way; these quick tests settle the rest:
- Hardness: can it scratch glass (hard, ~6+) or does a knife scratch it (softer)?
- Acid fizz: a drop of vinegar fizzes on limestone and marble (carbonates), not on granite or sandstone.
- Streak & grain: rub it on unglazed tile for its true powder colour, and look closely for grains, layers or crystals.
Frequently asked questions
How can I tell what kind of rock I have?
Start with a clear, well-lit photo and our AI will name the most likely rock and how confident it is. Then confirm with a few quick checks: how hard it is (does it scratch glass?), its streak color on unglazed tile, whether it fizzes with vinegar, and whether you can see grains, layers or crystals. Those four tests separate most common rocks.
Can AI really tell what kind of rock this is from a photo?
For many specimens, yes — colour, grain size, texture and layering are often enough to place a rock. But some rocks look almost identical in a photo, so we give you a confidence score and the at-home tests to confirm, instead of a confident guess that might be wrong.
What are the three main types of rock?
Igneous (cooled from molten rock — e.g. granite, basalt), sedimentary (compacted layers or grains — e.g. sandstone, limestone), and metamorphic (changed by heat and pressure — e.g. gneiss, schist, marble). Spotting which family a rock belongs to is the first step in identifying it.
Is it free?
Yes — your first 3 identifications are free, with confidence scores and how-to-confirm tips on every result.
Looking for a crystal or gemstone instead? Try the crystal identifier or browse the field guide.