Low-priced stock that sells at less than $1.00 per share. Often highly-speculative and volatile, such as start-up mining companies. While, in general, penny stock are considered high-risk securities, some penny stock mature into less-speculative investments. All penny stock are traded over-the-counter.
In its natural form, cork is also a very good fire retardant, although cork dust is actually extremely flammable (because here the cell structure has been broken down). Impermeable: Cork has a magic chemical in its cell membrane that makes it completely impermeable to liquids and gases.
We used to use the end of a burnt cork on our faces as camouflage! Cork is a natural material from the bark of the Cork Oak tree and this material has been known for donkey's years to protect the tree from death during natural wildfires. However that doesn't mean it is fire resistant - it will smoulder and blacken.