They are cored out of slate with a drill or drill press, then shaped. Here’s what I’ve found:
I don’t know about a video, but this is the website that the images came from, featuring much of the process:
The leftovers are sold as paperweights.
They are cored out of slate with a drill or drill press, then shaped. Here’s what I’ve found:
I don’t know about a video, but this is the website that the images came from, featuring much of the process: