Stoneye
Rock and mineral identifier
Free · In‑App Purchases · Designed for iPad. Not verified for macOS.
Stoneye identifies the rock in your hand — and shows its work.
Photograph the stone and Stoneye gives you a short list of candidates. Then it asks you questions you can answer at home: does it scratch glass, what colour streak does it leave on unglazed porcelain, does it break along flat faces. Each answer removes minerals from the list until one is left, or until the honest answer is "these two cannot be told apart without a lab".
WHY THIS IS DIFFERENT
Stoneye uses the model for one narrow job: reading the photo and proposing candidates. Every decision after that — which question to ask, which minerals to eliminate, what the final answer is — comes from a deterministic engine built on a table of 201 minerals, where every value is sourced and cited. The same answers always produce the same result.
WHAT WE MEASURED
We ran the engine against all 201 minerals in the table, three ways:
• From a photo's candidate list: 1 question typically, never more than 2
• Working through the whole table with no photo: 5 questions typically, never more than 7
• Wrong answers in all three runs: zero
We also measured what we could not do. Only 30 of the 201 minerals can be identified down to a single name by at-home tests. Roughly 4% of all mineral pairs cannot be separated at all this way. So Stoneye shows you two or three names when two or three names is the truth — that is the majority outcome, not a failure, and the app is built around it instead of hiding it.
IT TELLS YOU WHEN IT DOESN'T KNOW
The engine answers "I don't know" rather than guessing. A mineral name that has no entry in the table never reaches your screen — the server filters it, and the app filters it again without trusting the server.
SAFETY IS BUILT IN, NOT BOLTED ON
The streak and scratch tests grind the stone, and 25 minerals in the table are dangerous as dust — the asbestos group, and minerals carrying arsenic, lead, mercury, antimony, or radioactivity. The warning appears before you make the dust, only on the test that makes it, and only when a flagged mineral is still in the running. For the asbestos group the advice is not "be careful" — it is "don't do this test at all", and skipping costs you nothing.
WORKS WITHOUT A SIGNAL
The physical tests, the full 201-mineral key, the reference library and your collection all work entirely offline. Only the photo step needs the network, and when it is unavailable the app routes you to the offline key instead of failing.
FREE AND PAID
Unlimited and free: every physical test, the full dichotomous key across all 201 minerals, the reference library, and your saved collection. None of that costs us anything to run, so none of it is behind a wall.
The only counted step is photo identification, because it is the only one that goes to a server and costs money to serve. Free gives you 10 a month. Stoneye Pro raises that to 100, Stoneye Studio to 300. Monthly or yearly — you pick the ceiling you need.
We do not say "unlimited", because it would not be true. Every photograph you send costs us money to answer, and a number we cannot honour is a number we will not print. No weekly plan. No trial that charges you when you forget.
PRIVACY
No account. No sign-up. No database. Your photo is sent for identification and is not stored. Location data is stripped from the image before it ever leaves your phone.
WHAT THIS IS NOT
Stoneye is an educational tool for rockhounds, students and collectors. It is not a gemmological appraisal and not a valuation. Do not use it to decide what something is worth, whether it is safe to handle, or whether it is safe to use.
SUBSCRIPTION AND TERMS
Stoneye Pro and Stoneye Studio renew automatically — monthly or yearly — unless cancelled at least 24 hours before the period ends. Manage or cancel in your Apple Account settings.
Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Privacy Policy: https://stoneye.app/privacy
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
- When the photo shows a rock, its name now carries a "Best guess from the photo" label. The name comes from the photo alone, while the tests at home check the minerals inside; fine-grained dark rocks such as shale, slate and basalt can look alike in a photo, and the screen now says so.
- Small fixes and improvements.
The developer, Ahmet Karaca, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Purchases
- User Content
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Ahmet Karaca
- Size
- 45.3 MB
- Category
- Education
- Compatibility
Requires iOS 15.0 or later.
- iPhone
Requires iOS 15.0 or later. - iPad
Requires iPadOS 15.0 or later. - iPod touch
Requires iOS 15.0 or later. - Mac
Requires macOS 12.0 or later and a Mac with Apple M1 chip or later.
- iPhone
- Languages
English and 8 more
- English, Arabic, French, German, Japanese, Korean, Simplified Chinese, Spanish, Turkish
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- Stoneye Studio Yearly $69.99
- Stoneye Studio Monthly $12.99
- Stoneye Pro Yearly $29.99
- Stoneye Pro $4.99
- Copyright
- © 2026 Ahmet Karaca