Could they be rockwool cubes??
http://www.1-hydroponics.co.uk/grow-media.htm

Ian in the UK

Gene Schurg wrote:
Hi Orchid Fans,

I'm reading through the old Orchid magazines that I picked up several years
ago. It's fun to see what plants cost back in the 70s and 80s. Paph
rothschilidianum FCC/AOS for $4000! Other awarded plants for hundreds of
dollars for a division.

In the early 80s there was a product called Orchid Blocks that was being
sold. From pictures in the ad it looks like a block that sits on top of the
pot with a thin layer of moss on top. The orchid would grow around the
block and roots dangle down in the empty pot under the block.

It looks interesting. I was thinking I could cut a circle of wood (cedar
shingles) and place it on the shelf formed by the brim of a clay pot.
Drilling some holes in the wood circle would allow the same thing.

What ever happened to the Orchid Block idea? Anyone ever try them?

Good Growing,
Gene