Lithophytic/Rupiculous Mounts

[Uechi]

I am looking for a source for information on mounting Lithophytic orchids on rocks. It seems logical to me that if the orchids that fall into this category grow on rocks that a good rock mount would be just what they want. The question is what types of rocks, how to mount and orchid supply source for mounts. I assume that most of these orchids grow on rough surface limestone or granite but I don't know. Articles on rock dwelling orchids never seem to mention what type of rocks. I think it would be quite a dramatic display to have orchids growing happily on reasonably sized rocks. Help please.