A comment by Stephen M. Richard about
I've studied the basics of the rock classification (igneous, metamorphic, sedimentary), and I think the basic approach taken is sound. There are some points I'd quibble--I don't think of >2mm as being a good definition of 'coarse-grained', but at least they are trying for some consistent logic. What I think we can especially use from the BGS effort is to extract the various criteria used for classification (grain size, modal mineralogy, texture, origin) and make sure that the terms necessary to quantify the criteria are included in our word list. I plan to tackle this problem and hope to post some kind of summary for igneous rocks. steve
Further discussion of BGS scheme has some excellent features (this page):
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