Mine looks like it’s ceramic. From AMP’s website:
“Dropped Cases: If a cartridge falls out of the shell holder and into the machine, simply turn off the power at the back of the machine, remove the pilot and retrieve the cartridge. If already annealed, it will be HOT. For extremely short cartridges, a pair of long nosed pliers can be used to retrieve them. Dropping a hot case will not damage the annealer. A small amount of poly-carbonate at the bottom of the well may melt, but this is just cosmetic. Note: our Mark ll annealers feature a ceramic insert at the bottom of the inductor. No damage at all will result from dropping a hot case.
From time to time, debris can accumulate in the inductor air gap well. This can be removed by using a moistened cue tip or similar. If any ferrous material such as steel wool fragments has accumulated, they will adversely affect the magnetics of the inductor. Cleaning with several cue tips should fix the problem. A short spray of isopropyl alcohol down the inductor well before cleaning is helpful. Ensure the annealer is cool and unplugged before cleaning.“