A headstone, tombstone, or gravestone is a stele or marker, usually stone, that is placed over a grave. They are traditional for burials in the Christian, Jewish and Muslim religions, among others. In most cases they have the deceased’s name, date of birth, and date of death inscribed on them, along with a personal message, or prayer, but they may contain pieces of funerary art, especially details in stone relief. In many parts of Europe insetting a photograph of the deceased in a frame is very common.
A cemetery may follow national codes of practice or independently prescribe the size and use of certain materials, especially in a conservation area. Some may limit the placing of a wooden memorial to six months after burial, after which a more permanent memorial must be placed. Others may require stones of a certain shape or position to facilitate grass-cutting. Headstones of granite, marble and other kinds of stone are usually created, installed, and repaired by monumental masons. Cemeteries require regular inspection and maintenance, as stones may settle, topple and, on rare occasions, fall and injure people;[1] or graves may simply become overgrown and their markers lost or vandalised.

Restoration is a specialized job for a monumental mason. Even overgrowth removal requires care to avoid damaging the carving. For example, ivy should only be cut at the base roots and left to naturally die off, never pulled off forcefully. Many materials have been used as markers.
Fieldstones. In many cultures markers for graves other than enclosed areas, such as planted with characteristic plants particularly in northern Europe the yew, were natural fieldstones, some unmarked and others decorated or incised using a metal awl. Typical motifs for the carving included a symbol and the deceased’s name and age.
Granite. Granite is a hard stone and requires skill to carve by hand. Modern methods of carving include using computer-controlled rotary bits and sandblasting over a rubber stencil. Leaving the letters, numbers and emblems exposed on the stone, the blaster can create virtually any kind of artwork or epitaph.
Marble and limestone. Both limestone and marble take carving well. Marble is a recrystallised form of limestone. The mild acid in rainwater can slowly dissolve marble and limestone over time, which can make inscriptions unreadable. Portland stone was a type of limestone commonly used in England—after weathering, fossiliferous deposits tend to appear on the surface. Marble became popular from the early 19th century, though its extra cost limited its appeal.
Sandstone. Sandstone is durable, yet soft enough to carve easily. Some sandstone markers are so well preserved that individual chisel marks are discernible, while others have delaminated and crumbled to dust. Delamination occurs when moisture gets between the layers of the sandstone. As it freezes and expands the layers flake off. In the 17th century, sandstone replaced field stones in Colonial America. Yorkstone was a common sandstone material used in England.
Slate. Slate can have a pleasing texture but is slightly porous and prone to delamination. It takes lettering well, often highlighted with white paint or gilding. From Wikipedia