StoneTell
Rock ID & field guide for kids
Only for iPhone
Free · In‑App Purchases · Designed for iPhone. Not verified for macOS.
iPhone
Your kid keeps pocketing rocks. StoneTell turns every one into a case to crack, a story to hear and a numbered specimen card for their own Field Guide.
Snap a rock and StoneTell names its suspects — and says honestly how sure it is. Close call? A kid-safe test with a magnet, a streak or a drop of vinegar cracks the case. Then the rock tells its own story, and the find is stamped into your Field Guide.
Made for curious 8–12-year-olds, and for the grown-ups who end up holding the rocks.
HOW A WALK BECOMES A COLLECTION
• Snap it. Point the camera at any rock, or pick one of Chip's sample rocks. Chip, a small fluorite crystal, coaches the shot.
• Meet the suspects. StoneTell says "most likely", "probably" or "not sure yet". It never fakes a 100%.
• Run the test. When two suspects are close, Rock Detective walks you through a quick experiment: a fridge magnet, a streak on a tile, a fingernail, a piece of glass, a drop of vinegar. Tests that need a grown-up say so first.
• Hear the story. Every rock tells its story in its own words, and reads it aloud at a tap.
• Stamp it. Your find becomes a numbered specimen card, stamped and filed in your Field Guide.
A FIELD GUIDE THAT FILLS UP
• 32 rocks and minerals to discover, from quartz and pyrite to malachite and garnet
• Specimen cards with serial numbers, dates and where you found them
• A Field Map of your finds, plus 26 curated U.S. rock spots where families can collect (always check the rules first)
• Museum-style cutouts that lift your rock off its background
BEYOND THE APP
• Rock of the Day and Field Guide widgets for the Home Screen and Lock Screen
• An "Identify a Rock" control for Control Center, the Lock Screen and the Action button
• Siri and Shortcuts: "Identify a rock with StoneTell"
• Your specimens in Spotlight
• Visual Intelligence: StoneTell suggests its matches for a rock you're looking at
MADE FOR EVERY KID
• VoiceOver, Dynamic Type up to the largest accessibility sizes, and Reduce Motion throughout
• Fully in English and Simplified Chinese, written for each language rather than translated
• A dark mode that glows like fluorite under a UV lamp
FOR GROWN-UPS
• No ads, no accounts, no third-party analytics or trackers. Usage counts stay on the iPhone.
• Rocks are identified right on the iPhone. The photos your kid files stay on it too, in the Field Guide, and removing a rock deletes its photo.
• No photo is uploaded unless a grown-up turns on "Second opinion" in Field Kit. It's off by default and sits behind a grown-up gate. When it's on and Chip is unsure, that photo goes to StoneTell's server for a second look, and the server may ask an AI vision service. Our server doesn't keep the photo, the guess record is deleted after 30 days, and no name, account or location is ever sent.
• A grown-up gate guards StoneTell Pro, the Grown-up Corner, web links, the Settings app, sharing, email sign-up, Second opinion and deleting data.
• StoneTell Pro, one purchase shared with your family, unlocks the full stories of the 8 newest rocks (each opening is free), more second opinions each month, and the Grown-up Corner, where grown-ups see what their rock detective has found and read.
• Map pins are optional and stored only on the iPhone. A shared card shows at most the state, province or country.
A NOTE ON HONESTY
Rocks are hard to identify from a photo, even for geologists. Sometimes StoneTell isn't sure, and it tells you so. That's when the detective work begins.
Specimen photos by Wikimedia Commons contributors under Creative Commons licenses, credited by name in Field Kit › Photo credits.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
New in 1.2:
• 8 new rocks to discover: garnet, azurite, olivine, pumice, scoria, black tourmaline, flint and conglomerate
• Sharper rock recognition
• The second opinion now tells you when a photo isn't a rock
• Try a sample rock: three new practice rocks
• StoneTell Pro — buy once, shared with your family: the full stories of the new rocks, more second opinions each month, and the Grown-up Corner, where grown-ups can see what their rock detective has found and read, and export it
The developer, 泽峰 陈, 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 Linked to You
The following data may be collected and linked to your identity:
- Contact Info
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- User Content
- Identifiers
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- 泽峰 陈
- Size
- 108.1 MB
- Category
- Education
- Compatibility
Requires iOS 26.0 or later.
- iPhone
Requires iOS 26.0 or later. - Mac
Requires macOS 26.0 or later and a Mac with Apple M1 chip or later.
- iPhone
- Languages
- English and Simplified Chinese
- Age Rating
4+
- 4+
- Made for Ages 9–11
- In-App Purchases
Yes
- StoneTell Pro $9.99
- Copyright
- © 2026 Zefeng Chen
