For other uses of "Riverstone", see Riverstone

Riverstone

-Places:* Riverstone, New South Wales – a suburb of Sydney, Australia** Riverstone railway station, Sydney** Electoral district of Riverstone** Riverstone High School* Riverstone Terraces – a suburb of Upper Hutt, New Zealand...

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The Patuxent River

Patuxent River

The Patuxent River is a tributary of the Chesapeake Bay in the state of Maryland. There are three main river drainages for central Maryland: the Potomac River to the west passing through Washington D.C., the Patapsco River to the northeast passing through Baltimore, and the Patuxent River between...

 stone is the state gem of the U.S. state

U.S. state

A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of Maryland

Maryland

Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...

. It is an agate

Agate

Agate is a microcrystalline variety of silica, chiefly chalcedony, characterised by its fineness of grain and brightness of color. Although agates may be found in various kinds of rock, they are classically associated with volcanic rocks and can be common in certain metamorphic rocks.-Etymology...

, a cryptocrystalline form of quartz

Quartz

Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...

. It is only found in Maryland and its red and yellow colors reflect the Maryland State Flag.

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.