Obsidians break into the conchoidal fracture. It also renders obsidian the unfit stone for rings and bracelets like jewelry production. It means obsidian is easy to break and chipped by some impacts. It is termed as the compressive strength of rocks and obsidians fractured or permanently deformed at 0.15 N per square millimeter. When a compressive pressure (In Newton unit) is applied to the rocks, a permanent deformation of rocks takes place at a point of pressure. The occurrence of color is due to the presence of different trace elements in obsidian rocks. Rarely found colors of Obsidian rocks are :Ī very rare occurrence of obsidians is Blue, Orange, Red, and Yellow. The highest occurrence of obsidians is in Black, but it is also available in Brown, Green, or Tan. The streak of obsidian is white, but various colors occur in nature.įrequently found colors of Obsidian rocks are: It means it is heavier than water and dense medium as a mass. The density of obsidian is 2.55 g/cubic cm. It is measured in relevance to the density of water in gram per cubic centimeter of the mass. The density of rock is used to express specific gravity. Let’s see some significant properties of obsidians. These all property attributes determine the applications of obsidian rocks. Obsidians have various physical & visual properties, such as Hardness, Grain Size, Fracture, Streak (Colors), Porosity, Luster, and Strength. The point where magma cools due to airborne cooling effects.The point where magma comes into contact with water on the surface.
Along the edges of a sill or dike, which takes place under the surface and it is the only intrusive type.Along the edges of a dome of the volcano.Along the edges of a flow of magma or lava.Obsidian rock can form in a variety of cooling environments such as. It forms on the surface of the earth when magma or lava comes out due to volcanic phenomena and rapid cooling takes place. We have seen in the earlier section that obsidian is a type of extrusive rock. Alternate Names : Lava, Glassy Lava, Xaga, Royal Agate, Glass Agate, Volcanic Glass, Glass Gem, Guardian Gem, and Black Beauty.Class : Igneous Rocks Sub-Class : Medium Hardness Rocks.Let’s see the classification of obsidian rocks from the perspective of a geologist. Geological Classification of Obsidian Rocks: It has a smooth and uniform texture, which breaks with a conchoidal fracture. The cooling of lava takes place so rapidly that no chance remains for proper crystallization (Atomic Arrangements) and finds as an amorphous glass material. It forms when felsic lava extruded from a volcano onto the surface of the earth. Obsidian is a glassy igneous rock that comes in a wide range of colours and textures. When molten magma is cooling rapidly onto the surface of the earth and forms small crystals in the rocks, they are known as extrusive igneous rocks.
When molten lava/magma is cooling slowly below the surface of the earth and forms large crystals in the rocks, they are known as intrusive igneous rocks.
We know igneous rocks have two basic types: 1. Today, we are going to know Obsidian rock, which falls in the main class of igneous rocks. In the Limestone article, we learned how sedimentation occurs and the formation of sedimentary rocks takes place. We know three main classes of rocks, sedimentary, igneous, and metamorphic.
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