Is this rare to find in my yard

[emourtaul]

 

[jewelerguy]

since you don't say where your yard is, how would anyone know if it's a rare find for your yard? Looks like a geode to me, although rather flat. It's always important for people to understand when asking questions to provide as much detail as possible about the item. Also helps to list the size or include a common item in the pictures such as a coin or cigarette lighter or whatever to show the size/scale

 

[crashbandicoot]

Welcome to Treasurenet emourtaul,what jewelerguy said is the way to go.I don,t know what your rock is other than a rock,but it looks interesting.