Rockd
An app that shows the geologic map and rock layers under your feet.
What Rockd does
Rockd is a free geology app from a University of Wisconsin-Madison research team. It shows the geologic map and rock layers wherever you stand, so you know what kinds of rocks to expect. It doesn't identify rocks from photos, but it's a great partner for an app that does.
Open Rockd and it gives you a plain summary of the geology at your location, drawn from more than 290 geologic maps. You can explore a 3D globe, look at rock columns, see what the area looked like long ago, and follow links to research that mentions the rock units around you.
When you find something, log it as a check-in with photos and notes. You can record strike and dip with your phone's compass, save maps for use in the field, and share your finds or keep them private.
Here's the honest part: Rockd won't tell you what the rock in your hand is. What it does is narrow things down, because knowing you're standing on limestone or granite makes any guess much better. Pair it with a photo identifier and your guess is better grounded. Some recent Android reviews mention loading trouble, so check them if you're on Android.
Alternatives to Rockd
Who it's for
Skip it if: Anyone who wants to identify a rock from a photo.
Pricing
Free planRockd is free, with no in-app purchases listed on the App Store.
Prices can vary by country. Checked 19 Oct 2026.
What people like
- Completely free, from a university research team
- Makes any rock ID guess more grounded
- Field logging with offline map saving
Watch out for
- No photo identification
- Some geology jargon
- Some recent Android reviews mention loading issues
Want your own map of rock hunting spots? Build your own.
Describe your app idea and Bilt builds it. Free to start, on your phone in minutes.
Try this idea: “an app where I save the spots I go rock hunting, add photos of what I found at each one, and see them all on a map”
Questions people ask
Can Rockd identify a rock from a photo?
No. It shows the geology where you are, which helps you narrow down what a rock is likely to be.
Is Rockd free?
Yes, and the App Store lists no in-app purchases.
Does it work without a signal?
You can save maps ahead of time and add field notes offline.