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.
The liquid you rub over your fingernails is composed of acetone, which is highly flammable. Recently, in Cypress, Texas, a woman's body caught fire when a nearby candle ignited her nail polish remover. Flammable and combustible liquids don't actually catch fire themselves.