Set up a display case: lighting, UV, humidity

1. Materials first: glass or acrylic, powder-coated metal or sealed and lined wood; no oak, no raw plywood or MDF, no rubber gaskets in contact with specimens, no felt that has not been tested (some felts are acidic or sulphurous). Line shelves with inert foam or archival board; use acrylic or glass stands.

2. Lighting: LED, 2,700–3,500 K for warm minerals and fossils (higher for fluorite and blue minerals), high colour rendering (CRI 90+), and out of the case or well ventilated so it does not heat the interior. Halogen and incandescent bake a case; fluorescent tubes emit UV. Aim light from above and slightly in front so relief shows; a second, dimmer source from the side kills hard shadows.

3. UV: most fossils are indifferent to UV, but amber, some minerals (realgar, proustite, vivianite, some fluorites), coloured shells and every paper label are not. Museum-grade UV-filtering acrylic or film on the case glass and no direct sunlight on the case are the rules. Amber darkens irreversibly in years in a sunlit room.

4. Humidity: aim for 40–55 % RH and, more important, stability. A sealed case with silica gel conditioned to 45 % (Art Sorb or conditioned gel in a tray) buffers a room that swings; pyrite and marcasite get their own micro-climate at 30 % inside the case or stay out of it; amber does not go in the dry box. Put a small datalogger inside and look at it monthly.

5. Labels: a printed label with each piece — name, formation, age, locality, number — on rag paper or archival card, in the same font and size for every piece. Visitors read labels; a case without them is a rock shop.

6. Security and weight: heavy pieces low and near the back; shelves rated for the load; museum wax or clear mounts under pieces on glass shelves; a lock if children or cats have access.

7. Rotate. What is on display is what fades and dusts; give light-sensitive pieces a rest in the drawer, and use the rotation as the inspection schedule.