Of course they "forgot" to mention what the binder was. Norton and many other companies have there “secrets” for making products, who’s to say they don’t use some ”special” blend of refined clays (and a dash of yellow#68) to make the hone… but they will never admit.
Ordinary clay may not be consistent enough as a binder but there are plenty of refined clays out there, suitable for a home-made.
How about plaster of peris… that stuff they use to set broken bones, it’s a “clay” too.
Don’t remember the name right now but there is a type of clay used to make crucibles to melt metal, it’s brittle, mixed with an abrasive should make a fine hone (and the clay is easy to get too).
You could probably make a hone with epoxy and aluminum oxide powder… (may not be perfect for a razor but you get the idea, home-made-hone is within the realm of possibility).
Incidentally some industrial grinding wheels (used for polishing steal) are made of rubber and or epoxy resin as the binder.
It may not be practical to “home make” a grinding wheel, as you know those things rotate pretty fast, a lot can go wrong if there is a void, a crack, imbalance or the binder is improperly fired...
A razor hone will not be subjected to that kind of stress... it just sits there in a holder with the blade running over the top.
We would only have to be concerned with the purity an consistency of the binder (the clay) for our home made razor hone.