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Little is known about the history of the oldest exposed rocks in the area due to extensive metamorphism.This somber, gray, almost featureless crystalline complex is composed of originally sedimentary and igneous rocks with large quantities of quartz and feldspar mixed in. [1] The original rocks were transformed to contorted schist and gneiss, making their original parentage almost unrecognizable.
Decoupage or découpage ( / ˌdeɪkuːˈpɑːʒ /; [ 1] French: [dekupaʒ]) is the art of decorating an object by gluing colored paper cutouts onto it in combination with special paint effects, gold leaf, and other decorative elements. Commonly, an object like a small box or an item of furniture is covered by cutouts from magazines or from ...
Geode. A geode ( / ˈdʒiː.oʊd /; from Ancient Greek γεώδης (geṓdēs) 'earthlike') is a geological secondary formation within sedimentary and volcanic rocks. Geodes are hollow, vaguely spherical rocks, in which masses of mineral matter (which may include crystals) are secluded. The crystals are formed by the filling of vesicles in ...
The oldest Proterozoic metamorphic and igneous rocks were intruded with granites and pegmatite between 1.45 and 1.4 billion years ago. The Oracle Granite, near Tucson, the Ruin Granite, close to the Ray-Superior area, and the Zoroaster Granite at the base of the Grand Canyon all contain one to two inch long, pink orthoclase crystals.
A Petoskey stone is a rock and a fossil, often pebble-shaped, that is composed of a fossilized rugose coral, Hexagonaria percarinata. [1] Such stones were formed as a result of glaciation, in which sheets of ice plucked stones from the bedrock, grinding off their rough edges and depositing them in the northwestern (and some in the northeastern) portion of Michigan's lower peninsula.
The Old Red Sandstone describes a group of sedimentary rocks deposited in a variety of environments in the late Silurian, through the Devonian and into the earliest part of the Carboniferous. The body of rock, or facies, is dominated by terrigenous deposits and conglomerates at its base, and progresses to a combination of dunes, and sediments ...
Metamorphic rock, deformed during the Variscan orogeny, at Vall de Cardós, Lérida, Spain. Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock ( protolith) is subjected to temperatures greater than 150 to 200 °C (300 to 400 °F) and, often, elevated pressure ...
Cupstone. Cupstones, also called anvil stones, pitted cobbles and nutting stones, among other names, are roughly discoidal or amorphous groundstone artifacts among the most common lithic remains of Native American culture, especially in the Midwestern United States, in Early Archaic contexts. The hemispherical indentation itself is an important ...