Can I tell what is in a pill based on the color or logo?

Pills come in many shapes and sizes, and there are often 'copycat' pills with similar logos and colors but different ingredients.  Take for example these two 2C-B pills from 2010: "Rolex" and "playboy bunny" that are different logos, sizes, weights and colors but have the same ingredient (but maybe not the same amount of that ingredient).  The logo on the pill tends to be how manufacturers advertise, with different colors of the same logo tending to have the same ingredients, wieght and dimensions if they are made by the same group. For instance these two differently colored Fleur De Lis' from Tulsa both contain the same ratio of BZP and TFMPP, and are nearly identical except for color.

You can get a good idea of what substances are in your pills by checking www.ecstasydata.org and pillreports.com, and by using a testing kit (depending on which adulterants you are worried about you may only need 1 or 2 of the reagents).