Also known as grass markers, these memorials should be four inches thick and they come in just about any size that you desire. The advantage to this type of marker is that they are the least expensive of the styles.
The disadvantages are they are difficult to find when there are leaves and snow on the ground, and everything in the cemetery sits on them: grass clippings, fertilizers, ground water. All of these things can stain granite. Also, like with your sidewalk at home, the grass tends to grow up and over the top of the marker. Without regular trimming the grass can virtually cover a marker