"What rock is this?" might be the most-searched question in geology. A stone catches your eye on the beach, in the garden, or on a trail — and now it's sitting on your desk, unnamed. The fastest way to an answer is a photo-based identifier that reads the rock's features and tells you what kind it is.
The quickest way to identify a mystery rock
Skip the guesswork. With Fossil Identifier & Rock ID you photograph the rock and get an instant identification:
Take a close, clear photo. Fill the frame with the rock and use even daylight.
Tap Identify. The AI reads texture, luster, grain and structure and cross-references known rocks.
Get your answer. See the rock's name and type, how it formed, its geological range and typical locations.
Find out what your rock is
One photo, one answer — free and instant on iPhone and iPad.
Download freeWhat kind of rock did I find? The three families
Every rock belongs to one of three families, and knowing which helps the identification make sense:
- Igneous — cooled from molten rock. Think granite (coarse crystals) or basalt and obsidian (fine, glassy).
- Sedimentary — built from layers of sand, mud or shells. Sandstone, limestone and shale, often with visible layering — and the family most likely to hold fossils.
- Metamorphic — changed by heat and pressure. Marble, slate and gneiss, often banded or foliated.
Identifying rocks by colour and texture
You can narrow it down yourself before you even scan:
- Sparkly crystals you can see with the naked eye usually mean an igneous or metamorphic rock like granite or gneiss.
- Smooth layers or bands point to sedimentary rock such as sandstone or shale.
- A glassy, dark surface that breaks with sharp edges is often obsidian.
- Fizzing under a drop of vinegar suggests limestone or another carbonate.
The app confirms these hunches and adds the details colour alone can't give you.
"What is this rock I found on the beach?"
Beach stones are tumbled smooth, which hides texture — so take an extra photo of any chipped surface. Common beach finds include quartz, agate, jasper, flint and fossil-bearing limestone. Scan a few of your favourites and you'll quickly learn to spot them by eye.
Frequently asked
Can an app really tell what rock this is from a picture?
Yes. Modern image-recognition models identify rocks by matching visual signals — texture, luster, structure — to thousands of known examples. Clear, close-up photos give the best results.
Is it free to find out what my rock is?
Yes, the app is free to download and try. For the full method, see our rock identifier guide.