Auguste Michel-Lévy
Encyclopedia
Auguste Michel-Lévy was a French
geologist
. He was born in Paris
.
He became inspector-general of mines
, and director of the Geological Survey of France. He was distinguished for his researches on extrusive rocks, their microscopic structure and origin; and he employed the polarizing microscope early on for the determination of mineral
s. In his many contributions to scientific journals he described the granulite
group, and dealt with pegmatite
s, variolite
s, eurites, the ophite
s of the Pyrenees
, the extinct volcano
es of Central France, gneiss
es, and the origin of crystalline schist
s.
He wrote Structures et classification des roches éruptives (1889), but his more elaborate studies were carried on with F Fouqué
. Together they wrote on the artificial production of feldspar
, nepheline
and other minerals, and also of meteorite
s, and produced Minéralogie micrographique (1879) and Synthése des minéraux et des roches (1882). Levy also collaborated with Alfred Lacroix in Les Minéraux des roches (1888) and Tableau des minéraux des roches (1889).
Michel-Lévy pioneered the use of birefringence
to identify minerals in thin section
with a petrographic microscope
. He is widely known for the Michel-Lévy interference colour chart
, which defines the interference colors from different orders of birefringence.
He also created classification schemes for igneous rocks which accounted their mineralogy, texture, and composition, and showed that igneous rocks of different mineralogies could be formed from the same chemical composition, with different conditions of crystallization.
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...
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...
. He was born in Paris
Paris
Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...
.
He became inspector-general of mines
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
, and director of the Geological Survey of France. He was distinguished for his researches on extrusive rocks, their microscopic structure and origin; and he employed the polarizing microscope early on for the determination of mineral
Mineral
A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...
s. In his many contributions to scientific journals he described the granulite
Granulite
Granulites are medium to coarse–grained metamorphic rocks that have experienced high temperature metamorphism, composed mainly of feldspars sometimes associated with quartz and anhydrous ferromagnesian minerals, with granoblastic texture and gneissose to massive structure...
group, and dealt with 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, variolite
Variolite
Variolites are a group of dark green basic igneous rocks that, especially on weathered surfaces, exhibit pale colored spots, or spherules, that give them a pockmarked appearance...
s, eurites, the ophite
Ophite
Ophite may refer to:*Ophites, an ancient Gnostic sect in Syria and Egypt*A name for verd antique, a type of serpentinite building stone...
s of the Pyrenees
Pyrenees
The Pyrenees is a range of mountains in southwest Europe that forms a natural border between France and Spain...
, the extinct volcano
Volcano
2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...
es of Central France, gneiss
Gneiss
Gneiss is a common and widely distributed type of rock formed by high-grade regional metamorphic processes from pre-existing formations that were originally either igneous or sedimentary rocks.-Etymology:...
es, and the origin of crystalline schist
Schist
The schists constitute a group of medium-grade metamorphic rocks, chiefly notable for the preponderance of lamellar minerals such as micas, chlorite, talc, hornblende, graphite, and others. Quartz often occurs in drawn-out grains to such an extent that a particular form called quartz schist is...
s.
He wrote Structures et classification des roches éruptives (1889), but his more elaborate studies were carried on with F Fouqué
Ferdinand André Fouqué
Ferdinand André Fouqué was a French geologist and petrologist.He was born at Mortain, in the Manche département....
. Together they wrote on the artificial production of feldspar
Feldspar
Feldspars are a group of rock-forming tectosilicate minerals which make up as much as 60% of the Earth's crust....
, nepheline
Nepheline
Nepheline, also called nephelite , is a feldspathoid: a silica-undersaturated aluminosilicate, Na3KAl4Si4O16, that occurs in intrusive and volcanic rocks with low silica, and in their associated pegmatites...
and other minerals, and also of meteorite
Meteorite
A meteorite is a natural object originating in outer space that survives impact with the Earth's surface. Meteorites can be big or small. Most meteorites derive from small astronomical objects called meteoroids, but they are also sometimes produced by impacts of asteroids...
s, and produced Minéralogie micrographique (1879) and Synthése des minéraux et des roches (1882). Levy also collaborated with Alfred Lacroix in Les Minéraux des roches (1888) and Tableau des minéraux des roches (1889).
Michel-Lévy pioneered the use of birefringence
Birefringence
Birefringence, or double refraction, is the decomposition of a ray of light into two rays when it passes through certain anisotropic materials, such as crystals of calcite or boron nitride. The effect was first described by the Danish scientist Rasmus Bartholin in 1669, who saw it in calcite...
to identify minerals in thin section
Thin section
In optical mineralogy and petrography, a thin section is a laboratory preparation of a rock, mineral, soil, pottery, bones, or even metal sample for use with a polarizing petrographic microscope, electron microscope and electron microprobe. A thin sliver of rock is cut from the sample with a...
with a petrographic microscope
Petrographic microscope
A petrographic microscope is a type of optical microscope used in petrology and optical mineralogy to identify rocks and minerals in thin sections. The microscope is used in optical mineralogy and petrography, a branch of petrology which focuses on detailed descriptions of rocks...
. He is widely known for the Michel-Lévy interference colour chart
Interference colour chart
An interference colour chart, first developed by Auguste Michel-Lévy, is an optical mineralogy tool to identify minerals in thin section using a petrographic microscope. With a known thickness of the thin section, minerals have specific and predictable colours in cross-polarized light, and this...
, which defines the interference colors from different orders of birefringence.
He also created classification schemes for igneous rocks which accounted their mineralogy, texture, and composition, and showed that igneous rocks of different mineralogies could be formed from the same chemical composition, with different conditions of crystallization.
External links
- Modern Microscopy, Michel-Lévy Interference Color Chart
- Molecular Expressions Microscopy Primer, Michel-Lévy Birefringence Chart
- Nikon Microscopy U, Michel-Lévy Birefringence Chart
- Olympus Microscopy Resource Center, Michel-Lévy Birefringence Chart
- Carl Zeiss AG, Michel-Lévy Color Chart.