Free Android app

GeoCrystal The mineral and rock identifier app for collectors and geologists

Take a photo of a rock or a crystal and find out what it is. GeoCrystal combines AI identification, an encyclopedic catalog of minerals and gemstones that works offline, professional field tools and a personal collection manager in one free app.

Get it onGoogle Play See the features

Free · Contains ads · Optional supporter purchase · Available in 6 languages

AIphoto identification

Hundredsof mineral datasheets

Offlinecatalog and tools

6languages

Identifying a mineral from a photo with GeoCrystal's AI

What is GeoCrystal

A field guide to minerals in your pocket

GeoCrystal is a free Android app for mineralogy and geology developed by Starlyware, an independent software studio based in Chieti, Italy. It is designed for mineral collectors, geology and natural science students, geologists and anyone who picks up a stone on a hike and wonders what it is.

Take a photo or choose one from your gallery: the AI vision model analyzes the sample and suggests the most likely minerals or rocks, each with its probability and a link to the full datasheet. From there you can study hardness on the Mohs scale, luster, cleavage, fracture, streak and density, the chemical formula and Strunz classification, the crystal system and the geological origin.

When you find a piece worth keeping, add it to your personal collection with photos, date, GPS coordinates and find notes, and share your best specimens in the Community Showcase. In the field, the geological compass and clinometer measures strike and dip, while the geologic time scale and the Mohs hardness test guide help you read rocks like a geologist.

Features

Everything a mineral collector needs

Identification, an encyclopedic catalog, field tools and your collection, all in one app.

AI mineral identification

Photograph a rock, crystal or gemstone (or upload it from the gallery) and get a scientific identification with probabilities and a direct link to the datasheet.

Encyclopedic offline catalog

Hundreds of detailed datasheets on minerals, gemstones and geological sites worldwide, with hardness, luster, cleavage, fracture, streak and density.

Chemistry and crystallography

Chemical formula, Strunz classification, constituent elements, crystal system, geological origin and rare varieties.

Your specimen collection

Catalog your samples with high-resolution photos, date, GPS coordinates, find notes and your own numbering.

Community Showcase

Share your best pieces with other collectors and browse the specimens found by the community.

Geological compass & clinometer

Measure orientation, azimuth, strike and dip of rock layers with the built-in bubble level.

Geologic time scale

An interactive stratigraphic column based on the ICS international standard, from the eons to the Holocene.

Mohs hardness test

A practical guide to finding hardness in the field with reference minerals and everyday objects.

Mineral localities & birthstones

Find historic mineral localities and mines worldwide with coordinates and maps, and discover the birthstone of each month and its story.

Screenshots

GeoCrystal at a glance

Mineral datasheet with Mohs hardness, streak and chemical formula — Mineral datasheet

Personal mineral collection with photos and GPS coordinates — Your collection

Geological compass and clinometer measuring strike and dip — Geological compass

Interactive geologic time scale based on the ICS standard — Geologic time scale

How it works

From the field to your collection in three steps

Photograph the sample

Take a picture of the rock or crystal in good light, or pick a photo from your gallery.

Check the identification

Compare the suggested minerals, open their datasheets and confirm with simple tests such as hardness and streak.

Add it to your collection

Save the specimen with photos, place, date and notes and, if you like, share it in the Community Showcase.

Free & privacy

Free, independent and transparent

GeoCrystal is free to download and use. It contains ads, which keep it free.
The optional "Support the developer" purchase is a one-time contribution: it unlocks no features and only adds a Supporter label with a heart to your profile.
You can browse the catalog and use the tools without an account; a free account is needed to catalog your specimens and share them.
You can delete your account and all linked data at any time, from the app or by email.
Made by an independent developer in Italy, available in English, Italian, Spanish, French, German and Portuguese.

FAQ

Frequently asked questions about GeoCrystal

Yes. Take a photo or upload one from the gallery and GeoCrystal's AI vision model suggests the most likely minerals or rocks, with a probability for each and a link to the full datasheet. Photo identification is a starting point: for a reliable result, confirm it with physical tests such as hardness on the Mohs scale and streak color, which the app explains step by step.

Yes. GeoCrystal is free on Google Play and contains ads. An optional one-time purchase lets you support the developer: it does not unlock extra features.

The catalog of minerals and gemstones and the field tools work offline, so you can use them where there is no signal. AI identification, the Community Showcase and the sync of your collection need an internet connection.

No. You can explore the catalog and use the tools as a guest. A free account lets you catalog your own specimens and share them in the Community Showcase.

Mineral and gemstone collectors, geology and natural science students, geologists doing field work, rockhounds and nature lovers who want to understand the stones they find.

English, Italian, Spanish, French, German and Portuguese.