题目Some rocks are very hard. What is the hardest rock? A. diamond B. quartz C. obsidian D. gneiss 相关知识点: 试题来源: 解析 A。解析:diamond(钻石)是最硬的岩石。quartz(石英)、obsidian(黑曜石)、gneiss(片麻岩)都没有钻石硬。本题考查词汇比较。
What is Obsidian? Obsidian Rock Color:Deep black or blackish green Fracture:Conchoidal Mohs scale hardness:5 – 6 Luster:Vitreous Specific gravity:c. 2.4 Optical properties:Translucent Obsidian is a volcanic glass that occurs naturally as an extrusionaryigneous rock. ...
Obsidian, a type of rock, is primarily composed of mineraloids, lacking a crystalline structure. 2 Minerals Naturally occurring, inorganic substances with a specific chemical structure. Quartz and feldspar are two common minerals found in the Earth's crust. 2 Rocks Aggregates or combinations of on...
Obsidianis a natural volcanic glass that is formed as an igneous rock that is extrusive. Obsidian is produced by rapidly cooling felsic lava extruded from a volcano with minimal growth in crystals. It is commonly found within the margins of rhyolitic lava flows known as obsidian flows, where th...
What type of igneous rock is obsidian? What are foliated metamorphic rocks? What type of composition does an igneous rock have? What are some examples of extrusive igneous rocks? What is another name for igneous rocks? What minerals are found in igneous rocks?
What minerals are in obsidian rock? Which metamorphic rocks are likely to contain garnet? What is the thick old crust of Earth known as? What type of rock is the most difficult to identify? Why? What are Earth's major geological processes?
Rock ClassificationRocks are classified by how they are formed. There are three basic groups: Obsidian Igneous Rock Fossilicious Limestone Sedimentary Rock Gneiss Metamorphic Rock Coal Biogenic Rock igneous-rocks created by volcanic activity. ...
Natural glasses: Obsidian is a natural glass formed during an eruption of silica-rich magma. Shown here are Apache tears, mahogany obsidian, and snowflake obsidian. Minerals Amazonite (a green variety of microcline feldspar) Beryl (the mineral of aquamarine, emerald, and heliodor) Chrysocolla (a...
What Color is Obsidian? As mentioned, obsidian is produced during the rapid cooling of volcanic lava. It is a formed rock with very sharp edges, mostly used for cutting and piercing tools, and for scalpel blades for surgical purposes.
What is Green Obsidian Green obsidianis a type of natural glass that is characterized by its green color, which is the result of trace amounts of elements like iron and chromium, sometimes enhanced by gas bubbles trapped within the rock, creating a beautiful sheen or iridescence. It is a ...