Shelving and finding it again
Updated
Where a specimen physically lives, and the fact that the arrangement matters less than the record of it.
Two arrangements
Almost every collection is arranged either systematically, by species, or by locality.
A few are arranged aesthetically, which is a display decision rather than a storage one.
The choice shapes how the collection is used and it is worth making deliberately rather than drifting into.
By species
The default for a general collection. Specimens of the same species sit together, so comparison is immediate and gaps are obvious.
It suits a collection built around breadth of species, which is most micromount and thumbnail collections.
The weakness is that a locality suite gets scattered across the cabinet.
By locality
The default for a collection focused on one area, one mine or one region.
It keeps a suite together, which is how such a collection is actually studied and how it will be sold.
The weakness is the mirror: comparing two specimens of a species means walking the whole cabinet.
Finding it
Here is the part that matters more than the arrangement: record the location in the catalog.
Cabinet, drawer, position. Updated when anything moves.
With that field, the physical arrangement is a convenience rather than a retrieval system, and the collection can be rearranged whenever without losing anything.
Without it, the arrangement IS the index, and a collection that outgrows its owner's memory becomes unsearchable, which is the state most large private collections are actually in.