Search results
Results from the WOW.Com Content Network
Telluric iron is largely divided into two groups, depending on the carbon content. Type 1 is a cast-iron typically containing over 2.0% carbon, while type 2 ranges somewhere between wrought iron and a eutectoid steel. Both types tend to handle weathering in the elements very well, but tend to decompose and crumble very quickly in the dry ...
1: olivine crystallizes; 2: olivine and pyroxene crystallize; 3: pyroxene and plagioclase crystallize; 4: plagioclase crystallizes. At the bottom of the magma reservoir, a cumulate rock forms. Fractional crystallization , or crystal fractionation , is one of the most important geochemical and physical processes operating within crust and mantle ...
The Grouville Hoard (Le Câtillon II) is a hoard of an estimated 70,000 late Iron Age and Roman coins reported in June 2012. They were discovered by metal detectorists Reg Mead and Richard Miles in a field at an undisclosed location in the parish of Grouville on the east side of Jersey in the Channel Islands. It is the largest hoard ever found ...
The structure is inverse spinel, with O 2-ions forming a face-centered cubic lattice and iron cations occupying interstitial sites. Half of the Fe 3+ cations occupy tetrahedral sites while the other half, along with Fe 2+ cations, occupy octahedral sites. The unit cell consists of thirty-two O 2-ions and unit cell length is a = 0.839 nm. [15] [16]
However, in a series of experiments culminating in his 1915 paper, Crystallization-differentiation in silicate liquids, [91] Norman L. Bowen demonstrated that crystals of olivine and diopside that crystallized out of a cooling melt of forsterite, diopside, and silica would sink through the melt on geologically relevant time scales.
The tholeiitic magma series (/ ˌ θ oʊ l eɪ ˈ ɪ t ɪ k /) is one of two main magma series in subalkaline igneous rocks, the other being the calc-alkaline series. A magma series is a chemically distinct range of magma compositions that describes the evolution of a mafic magma into a more evolved, silica rich end member.
Material properties (size, color, texture) of fulgurites vary widely, depending on the size of the lightning bolt and the composition and moisture content of the surface struck by lightning. Most natural fulgurites fall on a spectrum from white to black. Iron is a common impurity that can result in a deep brownish-green coloration.
Ceylonite, named for the island of Ceylon, is a ferroan spinel with Mg:Fe from 3:1 and 1:1, and little or no ferric iron. Pleonaste is named from the Greek for 'abundant,' for its many crystal forms, and is distinguished chemically by low Mg:Fe ratios of approximately 1:3. It is sometimes used as a gemstone. [2]