Phillipsite
Encyclopedia
Phillipsite is a mineral of the zeolite
group; a hydrated potassium
, calcium
and aluminium
silicate, approximating to (Ca
,Na
2,K
2)3Al6Si
10O
32·12H2O
. (Also with sodium replaced by calcium: KCa
Al3Si5O16·6H2O). The crystals are monoclinic, but only complex cruciform twins
are known, these being exactly like twins of harmotome
. Crystals of phillipsite are, however, usually smaller and more transparent and glassy than those of harmotome. Spherical groups with a radially fibrous structure and bristled with crystals on the surface are not uncommon. The Mohs hardness is 4.5, and the specific gravity
is 2.2. The species was established by A. Lévy in 1825 and named after William Phillips
. French authors use the name Christianite (after Christian VIII of Denmark
), given by A. Des Cloizeaux in 1847.
Phillipsite is a mineral of secondary origin, and occurs with other zeolites in the amygdaloidal cavities of mafic
volcanic rock
s: for example in the basalt
of the Giants Causeway in County Antrim, and near Melbourne
in Victoria
; and in Lencitite near Rome
. Small crystals of recent formation have been observed in the masonry of the hot baths at Plombires and Bourbonneles-Bains, in France
. Minute spherical aggregates embedded in red clay
were dredged by the Challenger
from the bottom of the Central Pacific, where they had been formed by the decomposition of lava
.
Zeolite
Zeolites are microporous, aluminosilicate minerals commonly used as commercial adsorbents. The term zeolite was originally coined in 1756 by Swedish mineralogist Axel Fredrik Cronstedt, who observed that upon rapidly heating the material stilbite, it produced large amounts of steam from water that...
group; a hydrated potassium
Potassium
Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...
, calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
and aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
silicate, approximating to (Ca
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
,Na
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
2,K
Potassium
Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...
2)3Al6Si
Silicon
Silicon is a chemical element with the symbol Si and atomic number 14. A tetravalent metalloid, it is less reactive than its chemical analog carbon, the nonmetal directly above it in the periodic table, but more reactive than germanium, the metalloid directly below it in the table...
10O
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
32·12H2O
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
. (Also with sodium replaced by calcium: KCa
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
Al3Si5O16·6H2O). The crystals are monoclinic, but only complex cruciform twins
Crystal twinning
Crystal twinning occurs when two separate crystals share some of the same crystal lattice points in a symmetrical manner. The result is an intergrowth of two separate crystals in a variety of specific configurations. A twin boundary or composition surface separates the two crystals....
are known, these being exactly like twins of harmotome
Harmotome
Harmotome is a mineral, one of the rarer zeolites; a hydrated barium silicate with formula: 5Al5,Si11O32·12. It forms vitreous white well defined monoclinic crystals, often associated with calcite and other zeolites...
. Crystals of phillipsite are, however, usually smaller and more transparent and glassy than those of harmotome. Spherical groups with a radially fibrous structure and bristled with crystals on the surface are not uncommon. The Mohs hardness is 4.5, and the specific gravity
Specific gravity
Specific gravity is the ratio of the density of a substance to the density of a reference substance. Apparent specific gravity is the ratio of the weight of a volume of the substance to the weight of an equal volume of the reference substance. The reference substance is nearly always water for...
is 2.2. The species was established by A. Lévy in 1825 and named after William Phillips
William Phillips (geologist)
William Phillips FRS was an English mineralogist and geologist.Phillips was the son of James Phillips, printer and bookseller in London. He became interested in mineralogy and geology, and was one of the founders of the Geological Society of London...
. French authors use the name Christianite (after Christian VIII of Denmark
Denmark
Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...
), given by A. Des Cloizeaux in 1847.
Phillipsite is a mineral of secondary origin, and occurs with other zeolites in the amygdaloidal cavities of mafic
Mafic
Mafic is an adjective describing a silicate mineral or rock that is rich in magnesium and iron; the term is a portmanteau of the words "magnesium" and "ferric". Most mafic minerals are dark in color and the relative density is greater than 3. Common rock-forming mafic minerals include olivine,...
volcanic rock
Volcanic rock
Volcanic rock is a rock formed from magma erupted from a volcano. In other words, it is an igneous rock of volcanic origin...
s: for example in the basalt
Basalt
Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...
of the Giants Causeway in County Antrim, and near Melbourne
Melbourne
Melbourne is the capital and most populous city in the state of Victoria, and the second most populous city in Australia. The Melbourne City Centre is the hub of the greater metropolitan area and the Census statistical division—of which "Melbourne" is the common name. As of June 2009, the greater...
in Victoria
Victoria (Australia)
Victoria is the second most populous state in Australia. Geographically the smallest mainland state, Victoria is bordered by New South Wales, South Australia, and Tasmania on Boundary Islet to the north, west and south respectively....
; and in Lencitite near Rome
Rome
Rome is the capital of Italy and the country's largest and most populated city and comune, with over 2.7 million residents in . The city is located in the central-western portion of the Italian Peninsula, on the Tiber River within the Lazio region of Italy.Rome's history spans two and a half...
. Small crystals of recent formation have been observed in the masonry of the hot baths at Plombires and Bourbonneles-Bains, in France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
. Minute spherical aggregates embedded in red clay
Clay
Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...
were dredged by the Challenger
Challenger
-Land vehicles:* Challenger trucks, a Canadian maker of heavy trucks* One of several British Army tanks:** Cruiser Mk VIII Challenger, in service during World War II** Challenger 1 tank, in service from the late 1980s to early 21st century...
from the bottom of the Central Pacific, where they had been formed by the decomposition of lava
Lava
Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...
.