from The Century Dictionary and Cyclopedia
- n. A white fibrous material made by blowing a stream of air or steam through molten slag as it comes from the blast-furnace or other metallurgical process. Usually known as mineral wool.
Sorry, no etymologies found.
Put the seed in a growth medium (soil or rock-wool), approximately the size of the seed under the surface (about 5 mm).
Vermiculite and possibly some rock-wool insulating materials may contain asbestos, a known health hazard.
This the main reason we use insulating rock-wool and NOT reflective tin-foil in our roofs!