The Patuxent River stone is the state gem (a form of agate) of the U.S. state of Maryland. Since it is found in red and orange this stone could also be referred to as carnelian. [1] It is found only in Maryland, and its colors reflect the flag of Maryland.
The Patuxent River stone became the state gem effective October 1, 2004, through the passage of Chapter 272, Acts of 2004; Code State Government Article, sec. 13-319. [2]
