“Built and maintained by a worldwide community of experts, Mindat.org is the world’s largest open database of minerals, rocks, meteorites and the localities they come from.”

Motivated by a passion sparked at an early age, Jolyon Ralph started this database from scratch in 1993 (DOS/Windows application; homemade hand-coded system) and shepherded its evolution through the internet stage to finally becoming an outreach program under the operation of the Hudson Institute of Mineralogy. The Hudson Institute of Mineralogy is a research, cultural and educational entity that was chartered by the Board of Regents of the University of the State of New York in 2003 and is a 501(c)(3) not-for-profit organization.

Mindat.org is a great resource when you need specific information on rocks and minerals, especially if you’re looking for depositional environment or locality data. The rich collection of photos also showcases the variety of forms of minerals. Although this database is maintained and enriched by an army of volunteers who strive to ensure the accuracy of the data, you may still want to consult one or two other sources to cross check the information for consistency.

This database is freely accessible and only requires registration (free of charge) if you wish to contribute entries (e.g., add localities, upload photographs) or take part in the message board. Contributors to the database are vetted to ensure accurate contributions and expert knowledge. Responsibilities of contributors include ensuring the accuracy of the data (e.g., precise locality information), providing references in the proper format, and owning the copyright of contributed data (text and images).

The site is easy and intuitive to use, from the single search box to the option of clicking on a category (mineral species, rock names, localities, photos, articles, and so on). The data is organized into mineral and locality pages with ample cross-linking to quickly navigate among the pages.

Mineral pages hold information relevant to individual minerals, rocks, meteorite types, gem materials, and other mineral or rock-like materials. The naming conventions for the different materials follow relevant standards and definitions as published by the International Mineralogical Association (IMA), the British Geological Survey (BGS) and the Meteoritical Society.

For a given substance, diagnostic information covers chemical and physical properties, crystallography and crystal structure, optical data, fluorescence, and more, although content will vary according to what’s available for that substance (see figure 2). References and Internet Links are also provided for more information. The Localities map and Locality List show the locations where the substance has been found or reported. The Locality List key can be used to gauge the degree of confidence one can ascribe to a given location. Localities tagged with TL (Type Locality for a valid mineral species) can be considered the most reliable. Links are present to navigate to the individual locality page.

Locality pages hold information relevant to individual localities. Localities are arranged in hierarchies to designate specific areas within larger, more general areas. An individual page generally has an interactive map, photos, geographic information, some history or description, a list of minerals from that site, plus references and links (see figure 3). As with the mineral pages, the amount of content for a given locality will depend on availability of information.

In addition, articles contributed by registered users can be found on a variety of topics – scientific articles, field trip reports, mining history, locality descriptions, advice for collectors, book reviews, etc.

Educators can use the mineral pages, articles and glossary as an introduction to minerals and rocks, and the Earth Sciences in general. The Information for Educators page offers some suggestions for an introductory level. Students can consult mindat.org as a resource for course assignments (e.g., a Geology 101 report) or research projects (e.g., chemical or elemental analysis of naturally-occurring chrysotiles, particularly located in California).

Sabine Lanteri, Science Liaison Librarian, University of Delaware

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