Moss agate is a semi-precious gemstone formed from silica. It is a form of agate which includes minerals of a green colour embedded in the chalcedony, forming filaments and other patterns suggestive of moss. The field is a clear or milky-white quartz, and the included minerals are mainly oxides of manganese or iron. ...more on Wikipedia about "Moss agate"
Nsutite is a form of mineral of manganese oxide [Mn(O,OH)H2O]. It is found in most large manganese deposits and was first discovered in Nsuta, Ghana. Since then, it has been found worldwide. Nsutite is a dull mineral with a hardness of 6.5-8.5 and an average density of 4.45 grams/cubic centimeter. It has a molecular weight of 87.24 grams/mole. Nustite is used as a cathode in zinc-carbon batteries, but synthetic manganese oxide is gradually replacing it. ...more on Wikipedia about "Nsutite"
plessite is a fine-grained mixture of the minerals kamacite and taenite found in the octahedrite iron meteorites. It occurs in gaps between the larger bands of kamacite and taenite which form Widmanstätten patterns. ...more on Wikipedia about "Plessite"
Portland Independent Top Whitbed is a kind of stone used to build "The Ashton Memorial" Lancaster. ...more on Wikipedia about "Portland Independent Top Whitbed"
Potash (or carbonate of potash) is an impure form of potassium carbonate ( K2 CO3) mixed with other potassium salts. Potash has been used since antiquity in the manufacture of glass and soap, and as a fertilizer. The name comes from the English words pot and ash, referring to its discovery in the water- soluble fraction of wood ash. ...more on Wikipedia about "Potash"
Prase is a green translucent chalcedony (quartz). It gets its coloring from chlorite and hornblende and has been used for engravings since antiquity. ...more on Wikipedia about "Prase"
Quartz is the most abundant mineral in the Earth's continental crust. It has a hexagonal crystal structure made of trigonal crystallized silica (silicon dioxide, SiO2), with a hardness of 7 on the Mohs scale. Density is 2.65 g/cm³. The typical shape is a six-sided prism that ends in six-sided pyramids, although these are often twinned, distorted, or so massive that only part of the shape is apparent from a mined specimen. Additionally a bed is a common form, particularly for varieties such as amethyst, where the crystals grow up from a matrix and thus only one termination pyramid is present. A quartz geode consists of a hollow rock (usually with an approximately spherical shape) with a core lined with a bed of crystals. ...more on Wikipedia about "Quartz"
Rose quartz is a type of quartz which exhibits a pale pink to rose red hue. The color is usually considered as due to trace amounts of titanium, iron, or manganese, in the massive material. Some rose quartz contains microscopic rutile needles which produces an asterism in transmitted light. Recent X-ray diffraction studies suggest that the color is due to thin microscopic fibers of possibly dumortierite within the massive quartz. It is rarely found in crystal form. When it is, its color is thought due to trace amounts of phosphate or aluminium. The color in crystals is apparently photosensitive and subject to fading. The first crystals were found in a pegmatite found near Rumford, Maine, USA, but most crystals on the market come from Minas Gerais, Brazil. ...more on Wikipedia about "Rose quartz"
Samarskite is a radioactive mineral with the empirical formula of ...more on Wikipedia about "Samarskite"
Sard is a reddish-brown chalcedony, SiO2, much used by the ancients as a gemstone. Pliny the Elder states that it was named from Sardis, in Lydia, where it was first discovered; but the probably name came with the stone from Persia (Pers. sered, yellowish-red). Sard was used for Assyrian cylinder-seals, Egyptian and Phoenician scarabs, and early Greek and Etruscan gems. The Hebrew odem (translated sardius), the first stone in the High Priest's breastplate, was a red stone, probably sard but perhaps carnelian or red jasper. Some kinds of sard closely resemble carnelian, but are usually rather harder and tougher, with a duller and more hackly fracture. Mineralogically the two stones pass into each other, and indeed they have often been regarded as identical, both being chalcedonic quartz colored with iron oxide. The range of colors in sard is very great, some stones being orange-red, or hyacinthine, and others even golden, while some present so dark a brown color as to appear almost black by reflected light. The hyacinthine sard, resembling certain garnets, was the most valued variety among the ancients for cameos and intaglios. Dark-brown sard is sometimes called sardoine, or sardine, while certain sards of yellowish color were at one time known to collectors of engraved gems as beryl. ...more on Wikipedia about "Sard"
Sascab is a naturally occurring mineral material described variously as "decomposed limestone", as " breccia", and as "the lime gravel mixture the Maya used as mortar." It has been used as a building and paving material in Mesoamerica since antiquity. In the context of pottery the term may also apply to mixtures (with clay and water) of a more finely divided form of the same material (described as "stone dust"). ...more on Wikipedia about "Sascab"
Shocked quartz is a form of quartz that has a microscopic structure that is different from normal quartz. Under intense pressure (but limited temperature), the crystalline structure of quartz will be deformed along planes inside the crystal. These planes show up as lines under a microscope, which are called shock lamellae. ...more on Wikipedia about "Shocked quartz"
The silicate minerals make up the largest and most important class of rock-forming minerals. They are classified based on the structure of their silicate anion group. ...more on Wikipedia about "Silicate minerals"
Smoky quartz or Smokey quartz, also known as Cairngorm or Cairngormstone is a brown variety of quartz caused through the natural (or artificial) irradiation of aluminium-containing rock crystal. A very dark brown to black opaque variety is known as morion. ...more on Wikipedia about "Smoky quartz"
Strontianite ( Sr C O3) is a mineral consisting of strontium carbonate, named after the village of Strontian, Lochaber, Scotland, where it was first discovered. This mineral is white, greenish, or yellowish in color, usually occurring in fibrous massive forms, but sometimes in prismatic crystals. ...more on Wikipedia about "Strontianite"
Taenite (Fe,Ni) is a mineral found naturally on Earth mostly in iron meteorites. It is an alloy of iron and nickel, with nickel proportions of 20% up to 65%. It is opaque with a metallic grayish to white color. The structure is isometric-hexoctahedral. Its density is around 8 g/cm³ and hardness is 5 to 5.5 on the Mohs scale. Taenite is magnetic. ...more on Wikipedia about "Taenite"
Tenebrescence, also known as reversible photochromism, is the ability of minerals to change colour when exposed to sunlight. The effect can be repeated indefinitely, but is destroyed by heating. ...more on Wikipedia about "Tenebrescence"
Thinolite is a mineral; a form of calcite showing unusual crystal form. ...more on Wikipedia about "Thinolite"
A thunderegg is a type of rock similar to a geode but formed in a rhyolitic lava flow and found only in areas of volcanic activity. Thundereggs are rough spheres, most about as big as a baseball. They look uninteresting on the outside, but slicing them in half may reveal highly attractive patterns and colors valuable in jewelry. ...more on Wikipedia about "Thunderegg"
Viluite is a name of a grossular garnet that is usually green. It comes from a river in Siberia called Vilyuy. Viluite is similar in appearance to vesuvianite. ...more on Wikipedia about "Viluite"
Wulfenite is a lead molybdate mineral with the formula Pb Mo O4. ...more on Wikipedia about "Wulfenite"
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