crystal regulator clocks

[Salmon Egg]

I am hoping someone could answer a curiosity question.

Just what is a crystal regulator clock and how does one work?

I have a sneaking idea it has nothing to do with an actual mechanism. It
would be surprising if the crystal in the name is a GLASS case,
erroneously called crystal, that covers the clock. The case allows you
to watch the clock work while the movement is protected from the
environment. The clock would have an ordinary mechanical regulator.

To me, I would think that the regulator should somehow have a true
crystal in the movement that affects the regulation. But I really do not
know, and Google has not helped.

--

Sam

Conservatives are against Darwinism but for natural selection.
Liberals are for Darwinism but totally against any selection.