Vivianite is an 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...

 phosphate mineral. It occurs as a secondary mineral found in a number of geological environments. It is usually found as deep blue to deep bluish green prismatic to flattened crystals.

It is formed by the alteration of ore deposits near the surface, or of primary phosphates in pegmatite

Pegmatite

A pegmatite is a very crystalline, intrusive igneous rock composed of interlocking crystals usually larger than 2.5 cm in size; such rocks are referred to as pegmatitic....

s. Vivianite crystals are often found inside fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

 shells, such as those of bivalves and gastropods, or attached to fossil bone.
Vivianite darkens upon exposure to oxygen.

Notable localities are Russia

Russia

Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

, Ukraine

Ukraine

Ukraine is a country in Eastern Europe. It has an area of 603,628 km², making it the second largest contiguous country on the European continent, after Russia...

, Namibia

Namibia

Namibia, officially the Republic of Namibia , is a country in southern Africa whose western border is the Atlantic Ocean. It shares land borders with Angola and Zambia to the north, Botswana to the east and South Africa to the south and east. It gained independence from South Africa on 21 March...

, England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

, and 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...

, Colorado

Colorado

Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...

 in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, and the town of Iwama, Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

.

It was first described in 1817 and named after John Henry Vivian

John Henry Vivian

John Henry Vivian was a Welsh industrialist and politician of Cornish extraction.Vivian was the son of John Vivian, of Truro, Cornwall, and his wife Betsey, daughter of the Reverend Richard Cranch, and the brother of Hussey Vivian, 1st Baron Vivian...

, who first discovered crystals of the mineral in Cornwall

Cornwall

Cornwall is a unitary authority and ceremonial county of England, within the United Kingdom. It is bordered to the north and west by the Celtic Sea, to the south by the English Channel, and to the east by the county of Devon, over the River Tamar. Cornwall has a population of , and covers an area of...

, England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

. The type locality

Type locality (geology)

Type locality , also called type area or type locale, is the where a particular rock type, stratigraphic unit, fossil or mineral species is first identified....

 is Wheal Kind, in St Agnes, Cornwall

St Agnes, Cornwall

St Agnes is a civil parish and a large village on the north coast of Cornwall, United Kingdom. The village is situated approximately five miles north of Redruth and ten miles southwest of Newquay....

.