A Bakerâs cyst is also known as a popliteal cyst or synovial cyst. It is a soft, fluid-filled lump that forms on the back of the knee. The lump is sometimes mistaken for a blood clot.
Geodes are typically agates. Agates are very common stones, and usually do not fetch a high price, but they are gorgeous to look at. Geodes in particular can be quite incredible, because they are like little miniature caves. On the outside, they look like plain, rough stones.
Geodes in sedimentary rocks are usually found in limestones, dolomites, and calcareous shale. In these deposits a gas-filled void can serve as the opening for geode formation. Shells, tree branches, roots and other organic materials often decay away to leave a void for the formation of mineral materials.