crucible

Meanings

1. A cup-shaped piece of laboratory equipment used to contain chemical compounds when heating them to very high temperatures.
2. A heat-resistant container in which metals are melted, usually at temperatures above 500°C, commonly made of graphite with clay as a binder.
3. The bottom and hottest part of a blast furnace; the hearth.
4. A very difficult and trying experience, that acts as a refining or hardening process.

Etymology

From Latin crucibulum (“night-lamp, metallurgic melting-pot”), apparently a derivative of crux (“cross”), perhaps by analogy to thūribulum (“censer”) and suffix -bulum, or from crucio (“to torment”).