Here, one will have to make their own arrangements for the tools to cut up the material to their size desired. They are also already cut up and sized per their specifications, which is a plus for those without machinery to do so. Here again, the risk of purchase, can vary in results for any graphite. There is other companies selling planchets, but, their prices are rather steeper, and are all unknowns as to diamagnetic effects of their products. One might sporadically check this web site for graphite.
All aspects are unknown and untried.
If one is after the best known diamagnetic graphite, the best known source still remains with the Martin Simon diamagnetic stands as previously mentioned. It is the only known source specifically chosen for its diamagnetic properties. The better diamagnetic stand is very strongly recommended, although slightly more costly, its much better. While the above are simply a reference to commercial sources, there are companys involved in their manufacturer of their own graphite material. Unless one is a engineer, or affiliated with a university, or is employed with a reputable company, the chances of obtaining such is for all purposes is nill and void for a private individual.