The Citrine Circle, a UK-based crystal shop, has created a free app that serves as a reference guide for over 400 crystals and minerals. The app is designed to help people keep track of their collection and learn more about the world of crystals and minerals. Users can browse through the crystals by name or image gallery, search for different crystals by country, or use the extensive filters to hone down their search further. Each crystal entry contains general information, a Geological tab detailing the Chemical Formula, Hardness, Colour Variations, Crystal System, Streak, Lustre and the main locations it can be found, and a Healing tab detailing the Metaphysical Properties, Chakra, Zodiac, Elemental, Numerology and Planetary associations.

The app also includes simple but fun games, including 4 different styles of Quiz to help users learn, and a Pairs memory game using the gorgeous crystal artwork. The app is not designed as an identification app, but rather to help users learn about each crystal. The app is not a fixed and exhaustive list of crystals, and the creators are always looking to add, update and expand the app to make it as useful as possible.

The creators of the app are a husband and wife team who founded and run The Citrine Circle. They have a passion for crystals and education, and will keep on updating the app with new crystals and educational articles. The app is not a replacement for the information available on their website, but rather a pocket edition that contains the most important information. The app is free to download and use, and is available worldwide.