The authors of these volumes assigned numbers to each mineral species. Galena for example is "2611", where "2" indicates it is a sulfide. "26" indicates it has "AX" stochiometry (since Galena is chemically PbS). "261" is the "galena group", and "2611" is galena itself. Collectors who admire this system may place these numbers on labels and/or use these numbers as part of a cataloging scheme. In particular, those who admire this scheme will usually organize their collection in "Dana order".

There are a number of problems with this way of doing things. First of all is the fact that you are up a creek without a paddle as far as dealing with silicate minerals. This shortcoming has been addressed by the publication of booklets providng a "Dana" organization of the silicate minerals. A somewhat more severe problem is what to do with all of the minerals that have been described since 1951.

The issue could be resolved and clarified by some clear thinking about what the purpose of a mineral classification really is. I won't attempt to answer that question (though it lies at the heart of the issue), but what I will say is that organizing a collection and classifying minerals are two different things and there is little if any purpose served by trying to do both at the same time.

I find organizing a collection alphabetically by species name to be simple and unambiguous. If I want to find Osarizawaite in a collection organized alphabetically I can typically lay my hands on the specimen in seconds. In a collection in Dana order, unless I am a very good mineralogist I will be hard put to know where to start. Even if I know it is a sulphate, I will be hard put to know where to look for it among the sulphates (and the situation is made even worse by the fact that this mineral was described subsequent to the seventh edition, and has no "official" dana number).

There have been some sad cases where books have been published and used a Dana-like system to organize minerals in the book. If I pull "Minerals of California" by Pemberton off the shelf and try to find the mineral "Aragonite" quickly, I will have little option other than to consult the index. By contrast, I can grab "Minerals of Arizona", which is organized alphabetically and thumb quicly to any species.

For some reason that I don't understand, proponents of the Dana system for organizing a collection can have an almost religious zeal for advocating this method. This is not my problem, and hopefully not yours either.