Here ya go
I've used the tumbled river rock for the Phal, and done the same, with smaller pebbles for the Lycaste in the pot, as it requires high humidity too. It really doesn't matter what you use as long as the orchid pot doesn't sit in the water. Gravel is commonly used, but you need to mound it up so the plant doesn't sit in water. The more surface of rock, the more evaporation.
