[analog31]

Cracking teacups was a concern.

I visited a fascinating museum with a ceramics collection, and it included an exhibit with a history of ceramics. Earlier ceramics had this problem. Apparently, bone china -- with some bone mixed in -- created a tougher material that was less prone to cracking under the rapid temperature shock. As ceramics improved over the decades, it became a non-issue.

I suspect that letting the heat spread out over a larger area at the bottom of the cup might have alleviated cracking. That's a speculation of course.

I wonder if this is why the Russians drank tea from glasses. My mom has some lovely Russian tea glasses with silver holders.

[0cf8612b2e1e]

Granted, I have only ever had access to modern materials, but that feels like a basic a QC check during manufacturing. Pour boiling water straight into the cup. Designs that fail need to be reworked to be thinner/thicker/baked differently.

[analog31]

Essentially, the materials hadn't been invented, or were not widely known. The people who were manufacturing hard china kept their recipes a secret. Adding bone dust to the ceramic made it tough enough to withstand the temperature swing.

Also, mass manufacturing was in its infancy.