The resolution on your photo is really poor. Please post a different photo, maybe two from different perspectives. Also, here are a couple things you can do to help us identify your rock: backlight it with any bright light. If the rock glows, light passes through it, it is translucent. Is it heavy for its size? Can you scratch a piece of glass with the rock? Can you scratch the rock with a common nail? If it scratches glass or you cannot scratch it with a nail, then it is very hard. Is the rock very smooth like wax, or is the texture grainy. Is it magnetic. These are things we would look at to help us identify it. There are acid tests, there are streak tests. If the better pictures can't get us where we need to be, we will go over those. If possible add something familiar to your photos for perspective purposes. A ruler, or a standard coin, like a quarter.