what rock is this?

Forty-two things you can pick up on a Michigan beach, every one with the single observation that separates it from the stone it gets confused with. No app required, no guessing, no photograph of a rock fed to a machine that will confidently tell you the wrong answer.

sorted by how rarely you will find one

grail · 100 of each

• copper agatemineral
• isle royale greenstonemineral

ultra rare · 150 of each

• trilobitefossil
• datolitemineral
• thomsonitemineral

rare · 250 of each

• gowganda tilliterock
• kona dolomiterock
• puddingstonerock
• jaspiliterock
• lightning stonerock
• leland blueman-made
• frankfort greenman-made
• lake superior agatemineral
• yooperliterock
• native coppermineral

fossil · 500 of each

• crinoidfossil
• brachiopodfossil
• petoskey stonefossil
• charlevoixfossil
• horn coralfossil
• bryozoanfossil
• branching coralfossil
• stromatoporoidfossil
• chain coralfossil
• gastropodfossil
• cephalopodfossil

uncommon · 750 of each

• unakiterock
• red jaspermineral
• hematitemineral
• epidotemineral
• carnelianmineral
• black shalerock
• sea glassman-made

the bedrock · 1000 of each

• basaltrock
• graniterock
• gneissrock
• rhyoliterock
• limestonerock
• sandstonerock
• quartziterock
• quartzmineral
• banded chertrock

Keep track of what you find

The Rock Journal is a free field journal for your finds. It does not identify anything. It records what you found, where and when, and turns it into a card the rock groups can actually answer. Nothing leaves your phone unless you send it.