We have managed to secure a limited quantity of Chinese 12k (12,000) grit waterstones at a very keen price. These are ‘natural’ stones and very hard, much harder than either the Belgian stones or the Naniwas offered elsewhere on this site.
These stones offer a budget alternative to the two mentioned above and are ideal for ‘touching-up’ the edge of your straight razor when the strop can’t quite get it back to shave-readiness. I use one myself and can attest to their capabilities.
The downside? Well, they are a hard stone so cut slowly - you’ll need about fifty passes minimum. Also, quite a few of them have small chips to the edges - this doesn’t affect their performance and these can be removed with a dressing stone or wet’n’dry paper. Equally, they will probably need to be lapped before use. The usual method is with some wet’n’dry paper and a sheet of glass. This is reflected in the price.
The upside? An excellent finishing stone for anyone on a tight budget or who wishes to dip a toe into the water before committing to a much more expensive hone. I’d rate these as top value for money.