To answer this question it's first good to rule out whether it is poisonous or not. You can do that with our Top 10 Deadliest Mushroom List and being extremely careful of The Most Deadly Mushroom. 

Now that you have excluded what it is deadly do a brief scan of the image below...

Recognise anything? You probably have found one which is similar to the one that you are trying to identify. For a more precise identification have a look at our mushroom identifier tool...