MIT Textbooks vs Stoneye

MIT Textbooks is a search engine for all your classes, as well as a marketplace for buying and selling new and used textbooks from other MIT students and online vendors. We try to find you the best price, as well as the most convenient delivery options for all your class textbooks.

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