Rock Glossary


Most geological descriptions of localities contain a large number of rock names. Any self respecting rockhound knows common rocks like granite, limestone or gneiss. But what about rocks like melteigite, tinguaite or fenite? Or even exotic ones like khibinite, jakutite and torgolite? I made my point, petrology is pretty complicated, not at least because of the huge amounts of names and varieties. This page is just a glossary, briefly explaining the rocks I encountered in references about Russia. I also added a lot of rock names with Russian type localities. I also started adding pictures of  rock samples, which are often the backsides of my mineral specimen!

The rocks are named alphabetically. Rocks starting with mineral names are listed under their parent rock name. So Aegirine-Lujavrite can be found under the Lujavrite entry.

Alnöite is a lamprophyre consisting of biotite, augite, olivine and melilite.

Andesite is an extrusive rock, mainly composed of plagioclase feldspar and pyroxenes. In Russia it is common on the large stratovolcanoes of  Kamchatka. picture

Atatschite is a syenite rock from the upper regions of Magnitogorsk. (Morozewicz, 1902)

Basanite is an explosive volcanic rock (like Kimberlite). basanite is rich in feldsapoids and plagioclase. 

Beresite is a granite in which the orthoclase has been hydrothermally altered to muscovite. It was first described from Beresovsk by Rose in 1837 

Beringite is a Barkevikite trachyt with Bering Island, near Kamchatka, as type locality.

Beshtauite is granitic rock that consists of roughly equal amounts of sanidine, plagioclase and quartz. It was first found by Bayan in 1866 in Beshtau, Caucasus.

Byerezite is an essexite from the Byerez river, near Achinsk along the upper Enissei. (Erdmannsdörfer, 1928)

Carbonatite is a strange but interesting igneous rock. It consists mainly of the carbonates, calcite and / or dolomite. It is frequently associated with alkaline intrusions and often the source of rare minerals. The frequent association of carbonatites with alkaline intrusions lays in the fact that alkaline magmas are capable of dissolving carbondioxide and acidic magmas are not. Carbonatites occur for instance in Kovdor, Vuoryyarvi, Khibiny, Afrikanda and numrous other localities

Damkjermanite is a calcite bearing ultramafic lamprophyre. In Russia Damkjermanite occurs on Mys Tury.

Diorite is a common intrusive rock consisting of 80-100% of feldspar (mostly plagiocase), very little if any Quartz and sometimes up to 50% of dark minerals.

Fenite is a metasomatic rock. It is formed between the contact of alkaline intrusions and the surrounding rock, by alternation of the latter. Fenites can therefore be found in a rim around alkaline intrusions. Basically the main thing that happened is that sodium rich solutions penetrated the surrounding rock. Quartz will be replaced by Albite and biotite and amphiboles will be replaced by Aegirine and related minerals. When the fenitization is minor the structure of the original rock can still be recognized, but when the process  develops the Fenite will be indistinguishable from regular alkaline rocks of magmatic origin.

Fergusite can be regarded as a feldspar free lucite-syenite. In Russia Fergusite occurs in the Murun massif.

Foyaite is a nephelinesyenite. It is an intrusive rock occuring in alkaline intrusions. It is coarse grained and light grey Foyaite consists mainly of microcline, nepheline and aegirine.

Garewaite is an ultrabasic olivinespessartite. The rock was named after the upper regions of the Garewaya river, near Pavda in the Ural. (Duparc 1904)

Gladkaite is a quartzdiorite that occurs as veins in Dunite of Gladkaya sopka in the Northern Ural.

Gneiss is a common metamorphic rock, often showing a distinct banding between light feldspar and darker mica's. picture

Ijolite is a nephelinesyenite. It is a medium grained grey rock with idiomorphic nepheline grains. Minor minerals like aegirine, feldspar, titanite and lamprophyllite fill in the space between the nepheline.

Ijusite is an Essexite from Siutik, Ijuss river, along the upper Ennissei river. (Rackovskiy, 1911)

Imandrite is a hybride between nepheline syenite and Grauwacke, or an albitegranite. In contrast to the nephelinesyenites does Imandrite contain Quartz. This rock was named so by Ramsay and Hackman in 1894.

Issite is a feldspar free hornblende spessartite. It forms veins in dunite from Tvetli Bor along the Iss river in the Ural. (Duparc 1910)

Karite is a quartz rich aegirineporphyr. Type locality is the kara river, near Nerchinsk, Transbaikal. (Karpinsky 1903)

Kazanskite is aplagioclase bearing dunite from Kazansky mountain, Srednji Ural. (Duparc, 1916)

Kersanite a biotite-plagioclase lamprophyre.

Khibinite is a nepheline syenite. This massive to trachyoide  intrusive rock is medium to coarse grained and has a greenish color. It occurs of course in the Khibiny massif. Nepheline is the dominant mineral. The feldspar dominant variety is called rischorrite. The rock was named so by Ramsay in 1898. The exact type locality is Chasnachorr in Khibiny.

Kimberlite is an magmatic rock that occurs in ancient volcanic pipes. The rock is most famous as host of diamonds, although not all Kimberlites contain diamonds. Diamondiferous imberlite occurs on ancient, Precambrean terranes, like the Baltic Shield and in Yakutia.

Kosvite is an olivine magnetite pyroxenite from the Kosva river in the Ural. (Duparc 1901)

Kyshtymite is a corund rich anorthosite rock, known from Barsovska, near Kyshtym in the Ural. (Morozewicz, 1898)

Lamprophyre is a group name of dike rocks. Their composition can vary and they are often altered.

Lemesite is stromatolitic limestone from Lemesa in the Yuzhnye Ural. It is quarried for ornamental purposes. picture

Listwänite is a quartz-sericite-talc-calcite-dolomite rock. Listwänites are formed by the alteration of basic- and ultrabasic rocks by carbonated hydrothermal solutions, containing hydrogen sulphide. In effect the dark silicates and feldspars are replaced by sericite, carbonates and sulphides. Listwänites occur for instance in the Ural mountains.

Lujavrite is a nepheline syenite. It is a greyishgreen to black, middle to coarse grained intrusive rock. It occurs in alkaline intrusions. The main constituents are amphibole, aegirine nepheline and feldspar. Lujavrite has a trachytoide structure. Aegirine-Hornblende Lujavrite is an Aegirine-Hornblende rich variaty. Eudialyte-Lujavrite  consists of nepheline, aegirine, microcline and eudialyte.Lovozerite-Lujavrite is a rare rock. It is very similar to eudialyte-lujavrite, with lovozerite replacing eudialyte. Lovozerite-lujavrite occurs in small lenses in eudialyte-lujavrite. The type locality for Lujavrite is Angvundaschorr (Brögger 1890)

Malignite Loparite-Malignite is a rare rock occuring in the Lovozero massif. It consists of 80-85% of Loparite with 15-20% nepheline, aegirine and feldspar).

Marble is a well known metamorphic rock. It is formed by metamorphose of limestone and it consists mainly of intergrown Calcite crystals. It is used for ornamental purposes. Most famous marble quarries in Russia are near Sludyanka at the southern tip of Lake Baikal. picture

Melanite-Ouachitite is a melanite rich biotite monchiquit, discovered on  the southern part of Mys Tury.  (Kranck 1928)

Miaskite is an Oligoclase rich mica foyaite from Cheremshansk, Ural. (Rose 1893)

Missourite  consists mainly of pseudo-leucite and pyroxene. In Russia Missourite occurs in the Murun massif. It can be regarded as a feldspar free leucite-shonkinite.

Nephelinesyenite is a so called foid-syenite. It can be regarded as silica poor syenite, where because of lack of silica, feldspars are (partially) replaced the foid mineral nepheline. Nephelinesyenite consists of nepheline with a variable amount of feldspar (albite, orthoclase or microcline).

Nephelinite is a name originally used for nepheline rich effusive rocks. Later the name was redefined as olivine free basalt.

Ophiocalcite is an ornamental rock consisting of little serpentine mixed with calcite. In Russia Ophiocalcite is quarried in Satka in the Urals. picture

Ostraite is a spinel pyroxenite from Ostraya sopka in the Ural. (Duparc 1913)

Pavdite is a dark colored gabbro dioriteaplite from Pavda,northeast of Perm. (Duparc, 1916)

Phonolite is the extrusive equivalent of syenite.

Quartzite is a hard metamorphic rock that is formed by compressig sandstone. The rock basically consists of quartz grains cemented together with quartz. Quartzite is a common rock. It is for instance mined in Shokhsa, Karelia. picture

Quartzporphyr is just old Rhyolite. It is a littl altered and should be named 'paleorhyolite'. 

Rodingite is a weakly metamorphosed ultrabasic rock. It's mineralogy resembles some skarns. Rodingites are typically formed when two continents collide. Ultrabasic fragments of the ocean floor between the continents end up as Rodingites in the mountains that are formed by the collision. Russia's most famous Rodingite is Bazhenovo in the Ural.

Rischorrite is a nephelinesyenite named after mount Rischorr in the Khibiny massif. Rischorrite is a light grey poikilitic intrusive rock. It consists of feldspar, nepheline and aegirine. The feldspar occurs in typical square crystals. picture

Shonkinite is a very dark (often black) nepheline syenite with over 50% dark minerals, mostly Aegirine and Augite.

Skarn. Skarn is  metasomatically altered limestones. What happened is that a granite, or granite-like magma intruded limestone. The heat and pressure alter the limestone to marble. But right at the contact between the granite and the marble chemicals can be exchanged. With so much calcium it is no surprise that calcium silicates are formed. Typical skarn minerals are Wollastonite, Vesuvianite, Spessartine and many others. Often skarns are very rich in ore minerals. Pitkjaranta and Dalnegorsk are also skarns. There are many types of skarns depending mostly on the type of intruding rock. Some mineralogically interesting skarns contain high levels of boron. Examples are Solongo, Titovskoye, Tayozhnoye and a few similar deposits near Verkhoyansk. picure

Suevite is a metamorphic rock formed by the impact shock of meteorites. It is best known from the German Ries crater. The best known Russian locality is the Popigay crater in north eastern Siberia. Suevite is a breccia. This means the rock consists of broken pieces of the original rock, together with high pressure metamorphic minerals like Shistovite, Coesite, Diamond and glass. picture

Sviatonossite is an Andradite-sodium syenite formed from a granite and a skarn. The type locality is Sviatoy Noss in Transbaikal. (Eskola 1920)

Syenite is an intrusive rock that can be regarded as silica poor granite. It consists of mainly feldspar sometimes with minor mica and quartz. 

Tachyliparite is a potassium liparite from Medovka, Piatigorsk, northern Caucasus. (Derwies, 1905)

Taimyrite is a noseane sanidinite from alluvial deposits in the Taimyr river.

Tawite can be regarded as Ijolite with Sodalite instead of Nepheline. The type locality for this rock is Mannepakhk, near Tawajok river in Lovozero.

Tilaite is an olivine bearing gabbropyroxenite from mount Tilai in the middle Ural. (Duparc 1905)

Tinguaite is a fine grained igneous rock. It occurs in dykes and consists of feldspar, nepheline and aegirine..The amount of nepheline equals or supersedes the amount of feldspar. Tinguatite is best known as matrix rock of toilite samples from Takhtarvumchorr, Kola.

Turjaite is a nepheline melilitolite

Turjite is an alkaline lamprophyre. It can be regarded as an analcime-carbonate-alnöite, formed by the mixture of monchiquit or anlöite magma with carbonate magma. The type locality for this rock is Russian, Serka-Bolshaya on Mys Tury in Kola.

Umptekite is a sodium-amphibole syenite, discovered in 1894 by Ramsay in Umpyavr in the Umptek (=Khibiny) massif. 

Urtite is a nephelinesyenite. It is a dark greenish-grey fine to medium grained intrusive rock, occoring in alkaline intrusions. It consists of nepheline (70-90% with  aegirine and feldspar. Urtite has a porphyric structure. The type locality of Urtite is Parga in Lovozero. (Ramsay 1896)

Yakutite is an silica undersatuared igeous rock, occuring in the Murun massif.

Xenolith is not a rock, but more a phenomenon. A Xenolith is a piece of rock that ended up inside another rock. Mostly a xenolith is part of the roof of an intrusion, that fell into the melt. Because the composition of the roof and the melt are mostly different, the chunk of roof will be altered by the heat and chemistry of the melt. These alterations resemble the contact aureole of the intrusion. Consequently Xenoliths are mostly similar to rocks like skarn, fenite etc.