The more common term for calcium that is found in rocks is called calcite. This calcite can be found in limestone. There are many places where limestone can be found. Certain igneous rocks can make this calcite.
It just takes the right things to make the calcium mix with it. Feldspar is a type of rock that has calcium in it, but not all of the feldspar rocks. It is only a certain type. You may have heard of calcium carbonate. This is a common limestone which has calcium in it. If you are wanting to find rocks that have calcium in it, then the best thing that you can do is to conduct a search for both limestone and feldspar.
Think of it as limestone, a sedimentary rock, found widely but also in concentrations like the White Cliffs of Dover, visible as you sail from France to England. I should point out that calcite, dolomite, limestone, and marble are all part of the carbonate group, which is based on calcium...and oxygen of course.
Limestone is almost pure calcium and so are crushed corals and invert shells. the carbonate group otherwise have rocks that are composed of more than 50% carbonate minerals,
Limestone is a type of rock that is highly rich in calcium carbonate. The major materials of limestone are the minerals calcite and aragonite, which are different forms of calcium carbonate. This type of rock is composed of the skeletal fragments of marine organisms such as molluscs and coral which are rich in calcium.
Marble is another type of rock that has high concentration of calcium. The major materials are calcite and dolomite.
Travetine, Tufa and chalk are forms of limestone with high concentration of calcium. Travetine is made from rapidly precipitated calcium carbonate. Chalk is form under deep marine conditions with gradual accumulation calcite shell which are highly rich in calcium.