Weloganite
Encyclopedia
Weloganite is a rare carbonate mineral with formula: It was discovered in 1967 and named for Canadian
geologist
Sir William Edmond Logan
(1798-1875). It was first discovered in Francon Quarry, Montreal, Canada and has only been reported from a few localities worldwide.
. The width of the crystals typically undulates down the length, forming crystals that widen in the middle or flare out at the end. Crystals are affected by light and can develop a white alteration coating over time. Weloganite is triboluminescent, producing blue light.
sill
in Montreal, Canada in the Francon Quarry where it was first discovered. It also occurs in the Mont Saint-Hilaire
district. Associated minerals include strontianite
, dawsonite
and calcite
. It has also been reported from the Pilansberg Complex of the western Bushveld Igneous Complex
in South Africa.
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
geologist
Geologist
A geologist is a scientist who studies the solid and liquid matter that constitutes the Earth as well as the processes and history that has shaped it. Geologists usually engage in studying geology. Geologists, studying more of an applied science than a theoretical one, must approach Geology using...
Sir William Edmond Logan
William Edmond Logan
Sir William Edmond Logan was a Scottish-Canadian geologist.Logan was born in Montreal, Quebec, and educated at the High School in Edinburgh and the University of Edinburgh . He started teaching himself geology in 1831, when he took over the running of a copper works in Swansea. He produced a...
(1798-1875). It was first discovered in Francon Quarry, Montreal, Canada and has only been reported from a few localities worldwide.
Properties
It is usually white, lemon yellow, or amber in color, and can be translucent. It crystallizes in the triclinic system and shows pseudo-hexagonal crystal forms due to twinningCrystal 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....
. The width of the crystals typically undulates down the length, forming crystals that widen in the middle or flare out at the end. Crystals are affected by light and can develop a white alteration coating over time. Weloganite is triboluminescent, producing blue light.
Occurrence
It occurs in an igneous carbonatiteCarbonatite
Carbonatites are intrusive or extrusive igneous rocks defined by mineralogic composition consisting of greater than 50 percent carbonate minerals. Carbonatites may be confused with marble, and may require geochemical verification....
sill
Sill (geology)
In geology, a sill is a tabular sheet intrusion that has intruded between older layers of sedimentary rock, beds of volcanic lava or tuff, or even along the direction of foliation in metamorphic rock. The term sill is synonymous with concordant intrusive sheet...
in Montreal, Canada in the Francon Quarry where it was first discovered. It also occurs in the Mont Saint-Hilaire
Mont Saint-Hilaire
Mont Saint-Hilaire , 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 Richelieu River. It is one of the Monteregian Hills...
district. Associated minerals include strontianite
Strontianite
Strontianite is an important raw material for the extraction of strontium. It is a rare carbonate mineral and one of only a few strontium minerals...
, dawsonite
Dawsonite
Dawsonite is a mineral composed of sodium aluminium carbonate hydroxide, chemical formula NaAlCO32. It crystallizes in the orthorhombic crystal system. It is not mined for ore. It was discovered in 1874 during the construction of the Redpath Museum in a feldspathic dike on the campus of McGill...
and calcite
Calcite
Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate . The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 380-470°C, and vaterite is even less stable.-Properties:...
. It has also been reported from the Pilansberg Complex of the western Bushveld Igneous Complex
Bushveld igneous complex
The Bushveld Igneous Complex is a large layered igneous intrusion within the Earth's crust which has been tilted and eroded and now outcrops around what appears to be the edge of a great geological basin, the Transvaal Basin. Located in South Africa, the BIC contains some of the richest ore...
in South Africa.