Bismuth
The visual gateway.
Melted and slowly cooled, bismuth crystallizes into iridescent stair-step hoppers. The rainbow colors on the surface are the natural result of a paper-thin oxide layer reflecting light. Safe to handle, easy to display, and the piece that quietly turns curious visitors into element collectors.
Suggested format: Raw crystalline specimen, medium (15 to 40 grams).
See the bismuth crystal