Potting medium: Black scoria sources

[Weebl]

I am looking for sources to get black scoria, exactly like the stuff indoor palms are planted in which Home Depot sells. It seems I only see orchids which come from hawaiian nursuries which are potted in this. I prefer black scoria to the red lava rock found in landscaping bags at home improvement centers as it has bigger pores (=more airflow) and is black so it will absorb more heat from the sun. Does anyone know of a continental US source which sells this?

[Lagoon]

I pick this up at my local hardware store. Its comes mixed in with red lava. Got it in the BBQ ile.
Good luck in you're search, Weebl

The black rock does look very cool!