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What is Shale?
Shale is a fine-grained sedimentary rock that forms from the compaction of silt and clay-size mineral particles that we commonly call “mud.” This composition places shale in a category of sedimentary rocks known as “mudstones.” Shale is distinguished from other mudstones because it is fissile and laminated. “Laminated” means that the rock is made up of many thin…
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Types of Sand Grains
The grains in a sandstone can be composed of mineral, rock, or organic materials. Which and in what percentage depends upon their source and how they were altered during transport. Mineral grains in sandstones are usually quartz. Sometimes the quartz content of these sands can be very high – up to 90% or more. These…
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Weathering and Transport of Sand
The grains of sand in a sandstone are usually particles of mineral, rock, or organic material that have been reduced to “sand” size by weathering and transported to their depositional site by the action of moving water, wind, or ice. Their time and distance of transport may be brief or significant, and during that journey…
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What is Sand?
To a geologist, the word “sand” in sandstone refers to the particle size of the grains in the rock, rather than the material of which it is composed. Sand-size particles range in size from 1/16 millimeter to 2 millimeters in diameter. Sandstones are rocks composed primarily of sand-size grains.
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What is Sandstone?
Sandstone is a sedimentary rock composed of sand-size grains of mineral, rock, or organic material. It also contains a cementing material that binds the sand grains together and may contain a matrix of silt- or clay-size particles that occupy the spaces between the sand grains. Sandstone is one of the most common types of sedimentary rock, and it is found in sedimentary…
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Other Materials of Quartz and Fuchsite
Other rocks are also confused with verdite. Green aventurine is a quartzite colored by flakes of fuchsite. Macrocrystalline quartz sometimes has a green color caused by abundant fuchsite inclusions. The jade minerals, jadeite and nephrite, have frequently been confused with verdite. This problem is compounded by some vendors who market verdite under the misnomer of “African jade”. Dyed quartzite and dyed chalcedony are also…
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Buddstone vs. Verdite
In nature, buddstone is often found in intimate association with verdite, and there is sometimes a gradient of one material into another. [6] People often use the names “verdite” and “buddstone” interchangeably – but there should be no confusion. The solution to this confusion is the Mohs hardness test. Buddstone (Mohs hardness of 7) is…
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What is Buddstone?
Buddstone is a bright green variety of chalcedony that derives its green color from abundant inclusions of fuchsite mica. As a chalcedony, buddstone has a hardness of about 7 on the Mohs scale – which makes it much more durable than verdite. It also polishes to a brighter luster. This makes buddstone the preferred material for…
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Uses of Verdite
Verdite is soft and it often has a uniform texture. Those properties make it a good stone for making small sculptures. The people of South Africa have used verdite for generations, and it is often considered to be part of their culture. Some verdite contains visible inclusions of red (ruby) corundum. Some sculptors have creatively integrated…
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What is Verdite?
“Verdite” is a trade name used for grayish green to bright green metamorphic rocks that derive their color from abundant inclusions of fuchsite, a chromium-rich variety of muscovite mica. It often exhibits a foliated texture. The name verdite is from the Latin word viridis, which means “green”. Verdite is found at numerous locations in South Africa, the Kingdom of eSwatini (formerly Swaziland), and Zimbabwe. It…