from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A rare blue or light yellow to brown crystalline mineral, the rarest of three forms of titanium dioxide, TiO2, used as a pigment, especially in paint.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. a blue or brown mineral, a form of titanium dioxide, used as a pigment
from The Century Dictionary and Cyclopedia
- n. One of the three forms of native titanium dioxid; octahedrite. In color it is indigo-blue, reddish-brown, and yellow; it is usually crystallized in acute, elongated, pyramidal octahedrons.
He said claims the ink was too recent because it contained a substance called anatase titanium dioxide could be rejected because medieval maps have been found with the same substance, which probably came from sand used to dry wet ink.
Rutile is made up mostly of titanium dioxide with two rarer polymorphs anatase or octahedrite, which is a tetragonal mineral of pseudo-octahedral habit, and brookite, which is an orthorhombic mineral, the Doctor explained to her.
One crystal form, anatase, is furthermore even capable, at least in theory, of splitting water molecules all by itself.
Pigments used included Prussian blue, first synthesized in 1704, and synthetic anatase (titanium dioxide), first created as pure white in 1923.
It consists largely of the minerals gibbsite Al (OH) 3, boehmite γ-AlO (OH), and diaspore α-AlO (OH), together with the iron oxides goethite and hematite, the clay mineral kaolinite and small amounts of anatase TiO2.
According to Purchasingdata. com, rutile titanium dioxide prices are down from a recent peak in November, while the price of anatase has been steady for the past six months.
Millennium Chemicals will push 6¢/lb price increases in January on the sale of all rutile - and anatase-based titanium dioxide (TiO2) products.
Titanium dioxide (anatase) $/lb 0.93 0. 85-1.00 0.94 0. 90-0.96 0.92
"The problem is if the anatase … came out of gneiss or any other natural source, it is going to have a totally different appearance than the anatase that appears on the Vinland map ink," he notes.
He also claims that the yellow-brown marks are actually a residue left behind after black ink flaked off the map, calling into question the findings that the anatase was only found in yellow ink.
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