Many different materials* have been used over the years for crafting monuments,  but almost all family monuments today are made of granite.  Here we explain a little bit about monument grade granite, and the major processes of transforming it into a monument; quarrying,  finishing, and engraving. There's also a page telling a little bit about "setting" (erecting) monuments in the cemetery.

* Selecting  continue  will step you through the monument making process outlined in the individual links in the paragraph above.