§ 01
Granularity.
Where Strunz fuses, Dana splits. Anhydrous and hydrated phosphates each get their own class — 38 vs. 40 — because the structural family is different.
The Dana system.
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Pick a class to start.
Dana threads chemistry through crystallography — class, type, group, then species. Pick any branch in the tree to surface its catalogued minerals.
§ 02
Four numerical levels.
Class · Type · Group · Species — every level is a number. Autunite is 40.2a.1.1: class 40, type 2a, group 1, the first species.
§ 03
Where Dana wins.
Ore-mineral and supergroup work leans on Dana — the larger taxonomy gives more places to put very specific structural variants without renaming the parent.