Identify a rock

Geoscopy atlas · field tool

Answer what you can see and test at home. Every answer narrows the 47 rocks and minerals in the atlas; skip anything you are not sure about.

New to this? Read the rock identification guide first.

A starting point, not a certificate. Many rocks look alike, and the atlas holds 47 specimens, not every rock on Earth. Use the best matches to open the specimen pages and compare the photos and the field check there.

01What does it look like overall?A rock is a mix of grains; a mineral is one substance, often a crystal.
02Can you see separate grains?Look with a hand lens or your phone camera zoomed in.
03Layers or bands?
04How hard is it?Try in this order on a clean spot: fingernail, then a steel knife, then scratch a glass bottle with the sample.
05Does it fizz with vinegar?A drop of vinegar (or dilute acid if you have it). Watch for bubbles.
06Magnetic?Does a fridge magnet stick or pull?
07Heavy for its size?Compare with a stone of the same size from the garden.
08Main colour
09Shine (lustre)
10StreakRub it on the back of a white tile. What colour is the powder line?

best.matches

Answer a question to see the closest specimens.

    SafetyDo not taste or lick unknown minerals. Some in the atlas contain arsenic (adamite, scorodite) or lead (galena, vanadinite, wulfenite, descloizite), and monazite is radioactive. Wash your hands after handling samples, and wear eye protection when you scratch glass.