Cumberlandite
Encyclopedia
Cumberlandite is the U.S. state
of Rhode Island
's state rock. It is only found in large concentrations on a 4 acres (16,187.4 m²) lot in Blackstone Valley
, Cumberland
, and in traces scattered throughout the Narragansett Bay
watershed. Due to its high amounts of iron
, it is slightly magnetic.
The rock was formed over 1.5 billion years ago by volcanic
activity. The rocks were discovered by settlers hundreds of years ago, and were initially deemed valuable for the manufacture of cannon
and farm tools in the 18th and 19th centuries. The rock also contains a relatively high level of titanium
, also valuable for the manufacture of tools. Colonists tried to make cannon from the rock during the Revolutionary War
, but the cannon cracked because of the weakness of the iron.
Cumberlandite weathers to a brownish black with white crystals. This is strikingly different from the weathered look of other rocks in Rhode Island's glacial deposits. It is also much denser than the granites and metamorphic rocks that are common in these deposits. The rock is common in glacial deposits just south of its source location, and can be found in deposits all the way to the southern shore of Narragansett. This combination of coming from only one location, being obviously different from other rocks, and being easily identified by members of the public all may have led to its being selected as the Rhode Island state rock.
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 Rhode Island
Rhode Island
The state of Rhode Island and Providence Plantations, more commonly referred to as Rhode Island , is a state in the New England region of the United States. It is the smallest U.S. state by area...
's state rock. It is only found in large concentrations on a 4 acres (16,187.4 m²) lot in Blackstone Valley
Blackstone Valley
The Blackstone Valley or Blackstone River Valley is a region of Massachusetts and Rhode Island. It was a major contributor to the American Industrial Revolution...
, Cumberland
Cumberland, Rhode Island
Cumberland is a town in Providence County, Rhode Island, United States, incorporated in 1746. The population was 33,506 at the 2010 census.-History:...
, and in traces scattered throughout the Narragansett Bay
Narragansett Bay
Narragansett Bay is a bay and estuary on the north side of Rhode Island Sound. Covering 147 mi2 , the Bay forms New England's largest estuary, which functions as an expansive natural harbor, and includes a small archipelago...
watershed. Due to its high amounts of iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
, it is slightly magnetic.
Volcano
2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...
activity. The rocks were discovered by settlers hundreds of years ago, and were initially deemed valuable for the manufacture of cannon
Cannon
A cannon is any piece of artillery that uses gunpowder or other usually explosive-based propellents to launch a projectile. Cannon vary in caliber, range, mobility, rate of fire, angle of fire, and firepower; different forms of cannon combine and balance these attributes in varying degrees,...
and farm tools in the 18th and 19th centuries. The rock also contains a relatively high level of titanium
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....
, also valuable for the manufacture of tools. Colonists tried to make cannon from the rock during the Revolutionary War
American Revolutionary War
The American Revolutionary War , the American War of Independence, or simply the Revolutionary War, began as a war between the Kingdom of Great Britain and thirteen British colonies in North America, and ended in a global war between several European great powers.The war was the result of the...
, but the cannon cracked because of the weakness of the iron.
Cumberlandite weathers to a brownish black with white crystals. This is strikingly different from the weathered look of other rocks in Rhode Island's glacial deposits. It is also much denser than the granites and metamorphic rocks that are common in these deposits. The rock is common in glacial deposits just south of its source location, and can be found in deposits all the way to the southern shore of Narragansett. This combination of coming from only one location, being obviously different from other rocks, and being easily identified by members of the public all may have led to its being selected as the Rhode Island state rock.