Blue is one of the three primary colours in the RYB colour model, as well as in the RGB (additive) colour model. It lies between violet and cyan on the spectrum of visible light. The eye perceives blue when observing light with a dominant wavelength between approximately 450 and 495 nanometres. Most blues contain a slight mixture of other colours; azure contains some green, while ultramarine contains some violet. The clear daytime sky and the deep sea appear blue because of an optical effect known as Rayleigh scattering. An optical effect called Tyndall effect explains blue eyes. Distant objects appear more blue because of another optical effect called aerial perspective.
Silver is a chemical element with the symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. The metal is found in the Earth's crust in the pure, free elemental form, as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite. Most silver is produced as a byproduct of copper, gold, lead, and zinc refining.
The mineral pyrite, or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula FeS2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral.
A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compounds. Pigments of prehistoric and historic value include ochre, charcoal, and lapis lazuli.
Turquoise is an opaque, blue-to-green mineral that is a hydrated phosphate of copper and aluminium, with the chemical formula CuAl6(PO4)4(OH)8·4H2O. It is rare and valuable in finer grades and has been prized as a gemstone and ornamental stone for thousands of years owing to its unique hue. Like most other opaque gems, turquoise has been devalued by the introduction of treatments, imitations and synthetics into the market. The robin’s egg blue or sky blue color of the Persian turquoise mined near the modern city of Neyshabur in Iran has been used as a guiding reference for evaluating turquoise quality.
Jasper, an aggregate of microgranular quartz and/or chalcedony and other mineral phases, is an opaque, impure variety of silica, usually red, yellow, brown or green in color; and rarely blue. The common red color is due to iron(III) inclusions. Jasper breaks with a smooth surface and is used for ornamentation or as a gemstone. It can be highly polished and is used for items such as vases, seals, and snuff boxes. The specific gravity of jasper is typically 2.5 to 2.9. A green variety with red spots, known as heliotrope (literally sun-turn, also known as, is one of the traditional birthstones for March. Jaspillite is a banded-iron-formation rock that often has distinctive bands of jasper.
Chalcopyrite ( KAL-kə-PY-ryte, -koh-) is a copper iron sulfide mineral and the most abundant copper ore mineral. It has the chemical formula CuFeS2 and crystallizes in the tetragonal system. It has a brassy to golden yellow color and a hardness of 3.5 to 4 on the Mohs scale. Its streak is diagnostic as green tinged black.
Basic copper carbonate is a chemical compound, more properly called copper(II) carbonate hydroxide. It is an ionic compound consisting of the ions copper(II) Cu2+
, carbonate CO2−
3, and hydroxide OH−
.
In mining, tailings are the materials left over after the process of separating the valuable fraction from the uneconomic fraction (gangue) of an ore. Tailings are distinct from overburden, which is the waste rock or other material that overlies an ore or mineral body and is displaced during mining without being processed.
Acid mine drainage, acid and metalliferous drainage (AMD), or acid rock drainage (ARD) is the outflow of acidic water from metal mines or coal mines.
Vivianite (Fe2+
Fe2+
2(PO
4)
2·8H
2O) is a hydrated iron phosphate mineral found in a number of geological environments. Small amounts of manganese Mn2+, magnesium Mg and calcium Ca may substitute for iron Fe2+ in the structure. Pure vivianite is colorless, but the mineral oxidizes very easily, changing the color, and it is usually found as deep blue to deep bluish green prismatic to flattened crystals.
Vivianite crystals are often found inside fossil shells, such as those of bivalves and gastropods, or attached to fossil bone.
In many languages, the colors described in English as "blue" and "green" are colexified, i.e. expressed using a single cover term. To describe this English lexical gap, linguists use the portmanteau word grue, from green and blue, a term coined by the philosopher Nelson Goodman—with a rather different meaning—in his 1955 Fact, Fiction, and Forecast to illustrate his "new riddle of induction". The alternative, bleen, is not really used.
Moses Harris was an English entomologist and engraver.
Kittatinny Mountain is a long ridge traversing primarily across Sussex County in northwestern New Jersey, running in a northeast-southwest axis, a continuation across the Delaware Water Gap of Pennsylvania's Blue Mountain. It is the first major ridge in the far northeastern extension of the Ridge and Valley province of the Appalachian Mountains, and reaches its highest elevation, 1,803 feet, at High Point in Montague Township. Kittatinny Mountain forms the eastern side of Wallpack Valley; the western side comprises the Wallpack Ridge (highest elevation: 928 feet above sea level.
Laurentien was a Canadian brand of art supplies owned by Sanford Canada. The line of supplies included coloured pencils, markers and crayons. The line of Laurentian coloured pencils was discontinued around 2012 and their websites no longer exist. Laurentien was marketed in the United States under the name Paradise.
Pure gold is slightly reddish yellow in colour, but coloured gold in various other colours can be produced by alloying gold with other elements.
The Northland Pyrite Mine, also known as James Lake Mine, Rib Lake Mine, Harris Mine or simply Northland Mine, is an abandoned underground mine in Northeastern Ontario, Canada, located on the southwestern shore of James Lake in Best Township of Temagami. It was operated by the Northland Mining Company during the early 1900s with the construction of a 91 m (299 ft) shaft and many open-cuts north of the shaft. Minerals present at the mine include chalcopyrite, pyrite and pyrrhotite, deposited in Precambrian volcanic rock of the Canadian Shield.
Varieties of the color blue may differ in hue, chroma, or lightness, or in two or three of these qualities. Variations in value are also called tints and shades, a tint being a blue or other hue mixed with white, a shade being mixed with black. A large selection of these colors is shown below.
Yellow Lakelet
Purple Lakelet
Azure Lakelet
Azure Lakelet
Green Lakelet
