There are more than 180 species of hallucinogenic mushrooms in the world with new species being discovered all the time. One of the biggest telling points of whether a mushroom contains psilcoybin or not is if it bruises a bluish color caused by psilocin activity within it.
If it bruises blue to almost black in color and has a spore print that is between a purple-brown to rusty-brown color then you can be almost certain that you have found a psilocybin mushroom.
Please understand that the potency levels listed below are based on the measurement of one specific mushroom and that every mushroom will vary in potency up or down by 1% or more. This chart and potency levels are to give you an idea in general about where that mushroom should generally be in regards to potency compared to other mushrooms.