David Michael Self on Nostr: #MinCup24 #corundum I posted this last year, but here it is again: This is a ...

#MinCup24 #corundum

I posted this last year, but here it is again:

This is a synthetic corundum rod from a hospital laboratory. These are called "industrial sapphire" despite the fact that they are pure Al2O3. Scratch resistant and non-reactive, a sapphire rod only a few cm long can be 2000C at one end and 20 C at the other, so you can test a wide temperature range with just one part.