For the shrimpkeepers:
Fluval Stratum is a compressed soil from the Mount Oso volcano in Japan, and it’s popular for aquarium plants but can also be used for certain houseplants.
“People are using it like crazy right now for rare plant propagations because plants go nuts in this stuff,” Lindsay says.
https://joegardener.com/podcast/houseplant-propagation-need-to-knows-lindsay-sisti/