Neptunite is a
silicate mineral
Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust.
In mineralogy, silica (silicon dioxide, ) is usually consid ...
with the formula
K Na2 Li(
Fe2+,
Mn2+)
2 Ti2 Si8 O24. With increasing manganese it forms a series with mangan-neptunite.
Watatsumiite is the variety with
vanadium
Vanadium is a chemical element with the symbol V and atomic number 23. It is a hard, silvery-grey, malleable transition metal. The elemental metal is rarely found in nature, but once isolated artificially, the formation of an oxide layer ( pas ...
replacing the titanium in the formula.
It was first described in 1893 for an occurrence in the Narssârssuk
pegmatite
A pegmatite is an igneous rock showing a very coarse texture, with large interlocking crystals usually greater in size than and sometimes greater than . Most pegmatites are composed of quartz, feldspar, and mica, having a similar silicic com ...
of West
Greenland
Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is t ...
.
[ It is also found within ]natrolite
Natrolite is a tectosilicate mineral species belonging to the zeolite group. It is a hydrated sodium and aluminium silicate with the formula . The type locality is Hohentwiel, Hegau, Germany.
It was named natrolite by Martin Heinrich Klaproth i ...
veins
Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated b ...
in glaucophane
Glaucophane is the name of a mineral and a mineral group belonging to the sodic amphibole supergroup of the double chain inosilicates, with the chemical formula ☐Na2(Mg3Al2)Si8O22(OH)2.
Glaucophane crystallizes in the monoclinic system.
Name
G ...
schist
Schist ( ) is a medium-grained metamorphic rock showing pronounced schistosity. This means that the rock is composed of mineral grains easily seen with a low-power hand lens, oriented in such a way that the rock is easily split into thin flakes o ...
within serpentinite
Serpentinite is a rock composed predominantly of one or more serpentine group minerals, the name originating from the similarity of the texture of the rock to that of the skin of a snake. Serpentinite has been called ''serpentine'' or ''ser ...
in San Benito County, California
San Benito County (; ''San Benito'', Spanish language, Spanish for "Benedict of Nursia, St. Benedict"), officially the County of San Benito, is a county (United States), county located in the California Coast Ranges, Coast Range Mountains of the ...
, US. It also occurs in Mont Saint-Hilaire
Mont Saint-Hilaire (English: Mount Saint-Hilaire; abe, Wigwômadenizibo; see for other names) is an isolated hill, high, in the Montérégie region of southern Quebec. It is about thirty kilometres east of Montreal, and immediately east of the ...
, Quebec
Quebec ( ; )According to the Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is one of the thirtee ...
and in the Kola Peninsula
sjd, Куэлнэгк нёа̄ррк
, image_name= Kola peninsula.png
, image_caption= Kola Peninsula as a part of Murmansk Oblast
, image_size= 300px
, image_alt=
, map_image= Murmansk in Russia.svg
, map_caption = Location of Murmansk Oblas ...
of Russia
Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...
.[
The mineral is named for ]Neptune
Neptune is the eighth planet from the Sun and the farthest known planet in the Solar System. It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times ...
, Roman god of the sea because of its association with aegirine
Aegirine is a member of the clino pyroxene group of inosilicate minerals. Aegirine is the sodium endmember of the aegirine- augite series. Aegirine has the chemical formula Na Fe Si2 O6 in which the iron is present as Fe3+. In the aegirine-augit ...
from '' Àgir'', the Scandinavian sea-god.[
The ]Gemological Institute of America
The Gemological Institute of America (GIA) is a nonprofit institute based in Carlsbad, California. It is dedicated to research and education in the field of gemology and the jewelry arts. Founded in 1931, GIA's mission is to protect buyers and ...
(GIA) identified an 11.78-carat faceted specimen as neptunite based on Raman spectroscopy
Raman spectroscopy () (named after Indian physicist C. V. Raman) is a spectroscopic technique typically used to determine vibrational modes of molecules, although rotational and other low-frequency modes of systems may also be observed. Raman sp ...
.
References
Phyllosilicates
Potassium minerals
Lithium minerals
Sodium minerals
Titanium minerals
Monoclinic minerals
Minerals in space group 9
{{silicate-mineral-stub