Gneiss got its name from Erzgebirge (Germany) miners. « Gneiss » comes from the German words gneis,...
Scope noteDuring volcanic eruptions, high-temperature lava (1100-1200°C) is expelled and sometimes sprays over several...
Scope noteWhen standing at the foot of a chalk cliff, it is difficult to imagine the mechanism behind the formation of...
Scope noteIn Normandy, a few metres thick grey deposit can be found at the foot of the cliffs between Le Havre and...
Scope noteEclogite derives its name from the Greek word eklogê, which means « choice ». This metamorphic rock is an...
Scope noteThe cliffs of Normandy are composed of alternating layers of chalk and flint. Flint is a very hard...
Scope noteGabbro is named after a village in Tuscany (Italy). The colour of this volcanic rock varies from bluish grey...
Scope noteGlaucophanite is commonly known as « glaucophane schist » or « blueschist ». This high-pressure...
Scope noteGranite is a rock commonly associated with the coast of Brittany. It is a very common clear-coloured type of...
Scope noteMarble derives its name from the Greek word marmaros, which means « shining stone ».
Scope noteAlso known as « obsidian glass », obsidian got its name from Roman general Obsius, who was the first to...
Scope noteSandstone is a clastic sedimentary rock. It means is composed of fragments – or clasts – broken off other...
Scope noteSchist is a metamorphic rock with flat sheet-like grains. It contains elongated minerals arranged in roughly...
Scope noteA volcanic bomb is a porous and honeycomb mass of molten rock violently expelled in a viscous form. As it...
Scope noteThe Museum's petrology collections
Petrology is the branch of geology which focuses on the study of the origin, composition, and structure of rocks. Rocks are naturally occurring solid aggregates of minerals. They are found almost always in solid form (find out more about the Museum's mineralogy collections).
The Museum's petrology collections help us understand the geological history of the area, but also the planet. Rocks are invaluable sources of information on how landscapes evolved and are also crucial in understanding the rock formation process.
Did you know that a stone could be soft, or could even smell ? From coccoliths to molten lava, get ready to discover what lies underneath our feet !
Cliffs, volcanoes, mountains : explore these various landscapes and what they are made from in just a few clicks !
Gneiss got its name from Erzgebirge (Germany) miners. « Gneiss » comes from the German words gneis, gneisig, which means « hard » and « strong ».
During volcanic eruptions, high-temperature lava (1100-1200°C) is expelled and sometimes sprays over several thousands of square miles. Once it cools down, it solidifies (at a temperature of approximately 1000°C). In 95% of cases, lava cools into basalt rock.
When standing at the foot of a chalk cliff, it is difficult to imagine the mechanism behind the formation of such a huge rock exposure. As incredible as it may sound, chalk cliffs result from the gradual accumulation of calcite shells from microorganisms called coccolithophores.
In Normandy, a few metres thick grey deposit can be found at the foot of the cliffs between Le Havre and Octeville-sur-mer. This deposit is called Kimmeridge Clay.
Eclogite derives its name from the Greek word eklogê, which means « choice ». This metamorphic rock is an unusually dense silicate rock has a massive texture. This type of rock was used during the Neolithic Age to produce polished axes.
The cliffs of Normandy are composed of alternating layers of chalk and flint. Flint is a very hard sedimentary rock which contains silica.
Gabbro is named after a village in Tuscany (Italy). The colour of this volcanic rock varies from bluish grey to dark grey, sometimes almost black, with greenish shades.
Glaucophanite is commonly known as « glaucophane schist » or « blueschist ». This high-pressure metamorphic rock belongs to the greenschist group.
Granite is a rock commonly associated with the coast of Brittany. It is a very common clear-coloured type of rock. It can be predominantly white, pink, or grey, depending on its mineralogy. Several white, pink, or black minerals are usually visible on its surface.
Also known as « obsidian glass », obsidian got its name from Roman general Obsius, who was the first to bring a sample of this stone from Ethiopia to Rome.
Sandstone is a clastic sedimentary rock. It means is composed of fragments – or clasts – broken off other rocks by physical weathering or erosion. Sandstone is composed mainly of sand-sized minerals or rock grains. During diagenesis, these sediments were cemented to form this rock.
Schist is a metamorphic rock with flat sheet-like grains. It contains elongated minerals arranged in roughly parallel layers. These minerals usually easily split off into flakes or slabs. Schist is classified as a metamorphic rock, which means it is formed under extreme heat and pressure, even though it usually originates from sedimentary rocks.
A volcanic bomb is a porous and honeycomb mass of molten rock violently expelled in a viscous form. As it reaches the ground, this magma cools into solid spindle, cylindrical, or spherical-shaped fragments with cracked outer surfaces, hence the name « bread-crust bombs ».
Gneiss got its name from Erzgebirge (Germany) miners. « Gneiss » comes from the German words gneis,...
Scope noteDuring volcanic eruptions, high-temperature lava (1100-1200°C) is expelled and sometimes sprays over several...
Scope noteWhen standing at the foot of a chalk cliff, it is difficult to imagine the mechanism behind the formation of...
Scope noteIn Normandy, a few metres thick grey deposit can be found at the foot of the cliffs between Le Havre and...
Scope noteEclogite derives its name from the Greek word eklogê, which means « choice ». This metamorphic rock is an...
Scope noteThe cliffs of Normandy are composed of alternating layers of chalk and flint. Flint is a very hard...
Scope noteGabbro is named after a village in Tuscany (Italy). The colour of this volcanic rock varies from bluish grey...
Scope noteGlaucophanite is commonly known as « glaucophane schist » or « blueschist ». This high-pressure...
Scope noteGranite is a rock commonly associated with the coast of Brittany. It is a very common clear-coloured type of...
Scope noteMarble derives its name from the Greek word marmaros, which means « shining stone ».
Scope noteAlso known as « obsidian glass », obsidian got its name from Roman general Obsius, who was the first to...
Scope noteSandstone is a clastic sedimentary rock. It means is composed of fragments – or clasts – broken off other...
Scope noteSchist is a metamorphic rock with flat sheet-like grains. It contains elongated minerals arranged in roughly...
Scope noteA volcanic bomb is a porous and honeycomb mass of molten rock violently expelled in a viscous form. As it...
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