Search results
Results from the WOW.Com Content Network
The word turquoise dates to the 17th century and is derived from the Old French turquois meaning "Turkish" because the mineral was first brought to Europe through the Ottoman Empire. [ 6 ] [ 3 ] [ 4 ] [ 7 ] [ 8 ] However, according to Etymonline , the word dates to the 14th century with the form turkeis , meaning "Turkish", which was replaced ...
This is a list of types of sandstone that have been or are used economically as natural stone for building and other commercial or artistic purposes. Trans-regional [ edit ]
This formation is similar to the Applecross formation except that the sandstones are fine to medium-grained and there are very few pebbles. Almost all of these sandstone beds show the contortions shown by the older formation. The Applecross and Aultbea Formations together consist of an overall fining-upward sequence of sandstones.
Feldspathic sandstones are commonly immature or sub-mature. [1] These sandstones occur in association with cratonic or stable shelf settings. [1] Feldspathic sandstones are derived from granitic-type, primary crystalline, rocks. [1] If the sandstone is dominantly plagioclase, then it is igneous in origin. [1]
Leaders of states in the U.S. which have significant mineral deposits often create a state mineral, rock, stone or gemstone to promote interest in their natural resources, history, tourism, etc. Not every state has an official state mineral, rock, stone and/or gemstone, however.
They are closely related to sandstones in origin, and exhibit many of the same types of sedimentary structures, such as tabular and trough cross-bedding and graded bedding. [ 1 ] [ 2 ] [ 3 ] Fanglomerates are poorly sorted, matrix-rich conglomerates that originated as debris flows on alluvial fans and likely contain the largest accumulations of ...
It can be distinguished from adjacent Jurassic sandstones by its white to light pink color, meter-scale cross-bedding, and distinctive rounded weathering. The wide range of colors exhibited by the Navajo Sandstone reflect a long history of alteration by groundwater and other subsurface fluids over the last 190 million years.
Callaïs is the generic name for ancient green-blue precious stones used for making pendants and beads by western European cultures of the later Neolithic and early Bronze Age. The term includes turquoise and variscite but not jade. [1] [2] [3] "Callaïs" was described by Pliny the Elder as being paler than lapis lazuli. [4]