About this app

Turn your phone into a pocket geologist. RockID identifies rocks and minerals the way a real field geologist does — by their physical properties — completely offline. No signal, no account, no photos uploaded. Found a mysterious stone on a hike, a beach, or in your backyard? Don't guess from a blurry photo. Run a few quick field tests and let RockID narrow it down from a library of 580+ rocks and minerals. WHAT YOU CAN TEST • Hardness — does a fingernail, coin, knife, or glass scratch it? (the Mohs scale) • Streak — the color of its powder on an unglazed tile • Luster — metallic, glassy, dull, pearly, greasy • How it breaks — cleavage planes vs. uneven fracture • Magnetism — does a magnet stick? • Acid fizz — does a drop of vinegar make it bubble? (carbonates) • Heft — does it feel unusually heavy? Answer as many or as few as you like — every test is optional, and the more you do, the sharper the match. Results rank live as you go, and common finds are favored so you're not led astray by rare look-alikes. REFERENCE LIBRARY (PRO) Browse and learn every rock and mineral with detailed properties, formulas, where they form, common uses, and side-by-side tips for telling confusing pairs apart — pyrite vs. gold, calcite vs. quartz, and more. • 100% on-device — works deep in the backcountry • No subscription — one-time unlock for the full field guide • Identifying specimens is always free A learning and field-companion tool. Always confirm anything valuable or potentially hazardous with a qualified geologist.

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