In metallurgy, melchior is an alloy of copper, mainly with nickel (5–30%).
 Its name originates from Italian: "melchior" , which in turn is distorted French: "maillechort" , honoring the French inventors of the alloy, Maillot and Chorier.
 The term melchior sometimes refers not only to the copper-nickel alloys, but also ternary alloys of copper with nickel and zinc ("nickel silver") and even a silvered brass.
 Melchior is easily deformable by application of pressure, both in the hot and cold state.
 After annealing, it has a tensile strength of about 40 kg/mm.
 The most valuable property of melchior is its high resistance to corrosion in air, freshwater and seawater.
 Increasing content of nickel iron or manganese improves corrosion and cavitation resistance, especially in sea water and atmospheric water vapor.
 The alloy of 30% Ni, 0.8% Fe, 1% Mn and 68.2% copper is used in maritime shipping, in particular for the manufacture of condenser tubes.
 Thanks to the nickel, melchior, unlike brass and bronze, has not a yellow but a silver color.
 Together with high corrosion resistance, this silvery color is preferred for the manufacture of household utensils.
Melonite is a telluride of nickel; it is a metallic mineral.
 Its chemical formula is NiTe.
 It is opaque and white to reddish-white in color, oxidizing in air to a brown tarnish.
Mohawkite is a rare rock consisting of mixtures of arsenic , silver, nickel, skutterudite and copper, with the formula CuAs up to CuAs, and the most desirable material was usually found in white quartz matrix.
 It has a hardness of 3-3.5 and a metallic luster.
 It is named after the Mohawk mine where it was originally found.
 Colors range from brassy-yellow to metallic gray, and sometimes will have a blue or greenish surface tarnish.
 These colors come from its two main ingredients, the arsenic-rich copper minerals algodonite and domeykite.
 Its color may resemble pyrrhotite, but unlike pyrrhotite, mohawkite is not magnetic.
Nickel (II) Chromate (NiCrO) is an acid-soluble compound, red-brown in color, with high tolerances for heat.
 It and the ions that compose it have been linked to tumor formation and gene mutation, particularly to wildlife.
Brown diamonds are the most common color variety of natural diamonds.
 In most mines, brown diamonds account for 15% of production.
 The brown color makes them less attractive as gemstones because of the reduced glimmer, and most are used for industrial purposes.
 However, improved marketing programs, especially in Australia and the United States, have resulted in brown diamonds becoming valued as gemstones in recent years and even referred to as "chocolate diamonds".
 A significant portion of the output of Australian diamond mines is brown stones.
 A large amount of scientific research has gone into understanding the origin of the brown color.
 Several causes have been identified, including irradiation treatment, nickel impurities and lattice defects associated with plastic deformation; the latter is considered as the predominant cause, especially in pure diamonds.
 A high-pressure high-temperature treatment has been developed that heals lattice defects and converts brown diamonds into yellow or even colorless stones.
Widgiemoolthalite is a rare hydrated nickel(II) carbonate mineral with the chemical formula (Ni,Mg)(CO)(OH)·5HO .
 Usually bluish-green in color, it is a brittle mineral formed during the weathering of nickel sulfide.
 Present on gaspéite surfaces, widgiemoolthalite has a Mohs scale hardness of 3.5 and an unknown though likely disorganized crystal structure.
 Widgiemoolthalite was first discovered in 1992 in Widgiemooltha, Western Australia, which is to date its only known source.
 It was named the following year by the three researchers who first reported its existence, Ernest H. Nickel, Bruce W. Robinson, and William G. Mumme.
Adamite is a zinc arsenate hydroxide mineral, ZnAsOOH.
 It is a mineral that typically occurs in the oxidized or weathered zone above zinc ore occurrences.
 Pure adamite is colorless, but usually it possess yellow color due to Fe compounds admixture.
 Tints of green also occur and are connected with copper substitutions in the mineral structure.
 Olivenite is a copper arsenate that is isostructural with adamite and there is considerable substitution between zinc and copper resulting in an intermediate called "cuproadamite".
 Zincolivenite is a recently discovered mineral being an intermediate mineral with formula CuZn(AsO)(OH).
 Manganese, cobalt, and nickel also substitute in the structure.
 An analogous zinc phosphate, "tarbuttite", is known.
Cyclopentadienyl nickel nitrosyl is a blood-red color liquid.
 It was discovered by a team at The International Nickel Company.
 The molecular formula is (CH)NiNO.
 It can be prepared by treating nickelocene with nitric acid.
 It is extremely toxic (T+).
Nickelocene is the organonickel compound with the formula Ni("η"-CH).
 Also known as bis(cyclopentadienyl)nickel or NiCp, this bright green paramagnetic solid is of enduring academic interest, although it does not yet have any known practical applications.
Oxygen is a chemical element with symbol O and atomic number 8.
 It is a member of the chalcogen group on the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as well as with other compounds.
 By mass, oxygen is the third-most abundant element in the universe, after hydrogen and helium.
 At standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula O2 .
 Diatomic oxygen gas constitutes 20.8% of the Earth's atmosphere.
 As compounds including oxides, the element makes up almost half of the Earth's crust.

Question: What color is Cyclopentadienyl nickel nitrosyl?
Answer: blood-red color