Magic mushrooms are organic hallucinogens that have been used for thousands of years. What all these have in common is that they contain the mind-altering chemicals psilocybin and psilocin as well as traces of related chemicals. They are usually found as a small packet of dried vegetable matter, mainly grey in colour, with bluish and brownish bits, looking a bit like tree bark. It is often broken into small pieces, or sometimes ground into a grey powder.
Magic mushrooms have a distinctive smell and taste, which most people find unpleasant.
Occasionally it is available as fresh or semi-wilted whole mushrooms. It is possible to extract the active ingredients to make powder, capsules or pills, though this is not common. The minimum dose to feel any effect seems to be around a gram of dried mushroom. Usual doses are one and a half grams or more. A level teaspoon is about two grams.