I wrote this Review for the August 2025 edition of “StoneSpeak”, the Newsletter of the Southland Geological and Lapidary Club. The following is a slightly fuller version. My first Review of an online resource for “StoneSpeak” was of Peter Ballance’s e-book (2017) “New Zealand Geology: An Illustrated Guide”. The Southland Club’s website is here and its Facebook Page is here.
The website www.mindat.org describes itself as “the world’s leading authority on minerals and their localities, deposits, and mines worldwide”. Wikipedia describes it as “the largest mineral database and mineralogical reference website on the Internet”. I assume its name is a shortening of the phrase “mineralogical data”. The mineral entries, localities, and photographs in Mindat are really useful material even if you aren’t interested in a lot of the technical detail and resources in it. Mindat is not a website that will help you identify a stone you have found while fossicking. But once you have an idea of what mineral is in the stone, Mindat will tell you all about that.
Mindat is the brainchild of Jolyon Ralph, an Englishman. His story of its origin starts: “On Christmas Day 1993, there was nothing good on television. So I went upstairs to my room and started writing mindat”. He was 23 years old, and trying to produce mineralogical information in an accessible form. It was initially a personal computer database. He then uploaded it onto the internet as a website in October 2000. At the same time, it became a community-editable venture – other people could contribute material. Contributors to the database are vetted to ensure the accuracy of their material and expert knowledge. The history of Mindat as a website can be found here. Ralph was awarded the Mineralogical Society of America’s Distinguished Public Service Medal in 2011 for his work on Mindat (see here for a shaky and sometimes blurry YouTube video of the award presention). In 2014, Mindat was transferred to the Hudson Institute of Mineralogy who have operated it since.
The main strength of Mindat is the information it provides on different minerals. It includes useful descriptions as well as a lot of technical detail. However, the amount of information varies depending on how much work has been done on the entry. For example, “Chalcedony” is well-developed but “Hydrogrossular” is quite thin. Standard entries have a selection of photos at the top with links to more images, something I have used quite a bit. Entries have sections on such topics as physical properties, optical data and fluorescence, crystallography and crystal structure, chemistry, varieties, localities, and references.
The references provided by Mindat include key documents on a mineral and usually have URL links to download them – that is how I got access to Colin Hutton’s 1943 article on hydrogrossular where he first described it from samples in Nelson. The localities for a mineral don’t cover all places it can be found but usually just the most significant. For hydrogrossular, four New Zealand localities are recorded (despite the map initially showing only three): two in Northland, one in Marlborough and one on the West Coast. Te Waewae Bay (Gemstone Beach), where I find my hydrogrossulars, is not mentioned. As stated in a review of Mindat for educators and students, “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.”
The next Review is of the University of Auckland’s “Geology: Rocks and Minerals” Website. An Index to this Series is here.
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