Thread: Hone ID - Water. Stone., Natural Gemany

Vasilis, thank you for nice explanation. I will not use another acid. I will try to translate whole kanji stamps on stone and search more info.

Originally Posted by Vasilis

Almost all natural stones contain some carbonate minerals. These foam. As for synthetics it works only for some with magnesia binder or something similar. Norton won't foam. Naniwa superstones won't foam. Chocera will. King stones with resin binder won't either. Sigma won't. Barber stones won't. Chinese cheap ones won't.
As for naturals, the overwhelming majority of them are basic. They react with acid and get damaged, since their minerals are salts with SiO2 being the acid part, although really weak. That is replaced with the stronger one.
I don't know who started the rumor that "man made stones react with acid" but it's not true. And again, almost all natural stones do absorb liquids to a degree, so, next time you hone, there will be some acid in the solution as well, and steel rusts really fast in presence of acid. A stone that took some hundreds of millions of years to be formed getting damaged in an instant just to see if it bubbles, it doesn't sound right.
As for this stone, you can clearly see from the sides of the stone that it's a natural. See that letters 天然 ? It's a natural stone without question.
Edit; That's what is written on the right:
天然砥石 (tennen toishi, natural sharpening stone) ドイツ Germany. And something else but it should be less important to search the kanji by radicals, the above I know.
Google 天然砥石 and see the beauties, it became synonymous with Kyoto natural finishers.

Please, don't use acids on stones.

You might mention that the black Arkansas is used for gold testing where acid is purposely dropped on gold pieces atop the ark for proofing. No harm to the stone.
The quarries will sometimes immerse the stones in acid to insure no calcium is present.