Reason why I have asked is that there are sellers of Jaka who use material of dubious origin.
If it is from Radek then it is the original material. I know that for sure as we were together in the mine picking it. What puzzels me is the glittring in it. I will have to look through my collection of them. However I know that in the same meeting he was also giving out other hones e.g. Wallachian Sandstone hone.