Companions: magnetite, hematite, rutile, spinel, ulvöespinel. 2.4 Identification It is easily recognized by its pink colour, pleochroism (grey to brownish-pink), low reflectance, hardness, distinct anisotropism and frequent twinning, with the added criterion of its paragenesis (magnetite, rutile, hematite, etc.).
Haemo-ilmenite samples without coexisting magnetite have natural remanent magnetization to magnetic saturation ratios of only ∼ 2.5%, showing that the haematite …
A unique symplectitic intergrowth of magnetite + rutile is hosted by ilmenite in the gabbro of the Xinjie Fe-Ti oxide-bearing, mafic-ultramafic layered intrusion. The crystallization of rutile in the symplectite is probably formed by oxidation of ilmenite-hematite solid solution (Ilm-Hem ss ). Segregation of Fe 3+ in the Ilm-Hem ss at the rutile-host interfaces …
Fe–Ti oxides were either disseminated (5–15 vol%) or semimassive ores (20–50 vol%), represented by magnetite and ilmenite with minor hematite and goethite. They are found in cumulus and ...
The ilmenite-hematite (FeTiO 3-Fe 2 O 3) solid solution (Ilm ss) commonly occurs in layered intrusions (Harrison et al. 2000).Ilm ss tends to experience subsolidus re-equilibration and phase transformation during different T-f O 2 cooling paths, forming …
Experimental results indicate that intergrowths of magnetite-rutile and ilmenite-hematite, which are transformed from Ilm ss, are thermodynamically equivalent over a large temperature interval ...
Magnetite and ilmenite often occur together in oxide-rich zones of highly differentiated igneous rocks (Ashwal 1982), while magnetite and hematite may occur together in banded iron formations where fluid-present deformation facilitates oxidative transformation of magnetite to secondary hematite (Lagoeiro 1998). At oxidizing conditions near the ...
Combined electron microprobe, TEM, and X-ray diffraction (XRD) results indicate that hematite hosts reached a composition approximately ilmenite (Ilm) 14.4, and ilmenite hosts ∼Ilm 98. The bulk of the very stable NRM, which shows thermal unblocking ∼595–620°C, was acquired during final exsolution in the two-phase region canted ...
The crystallization of rutile in the symplectite is probably formed by oxidation of ilmenite-hematite solid solution (Ilm-Hem ss). Segregation of Fe 3+ in the Ilm-Hem ss at the …
Hematite is relatively pure Fe 2 O 3 with only minor Fe 2+, Ti, Al and Mn; solid solution is very limited between Hematite and magnetite (Fe 3 O 4), Ilmenite (FeTiO 3) and corundum (AL 2 O 3). Hematite and ilmenite form a complete solid solution at temperatures above 950°C. Hematite has several varieties, each with their own unique …
The Fe–Mg and Fe–Mn interdiffusion coefficients for ilmenite have been determined as a function of temperature and crystallographic orientation. Diffusion annealing experiments were conducted at 1.5 GPa between 800 and 1100 $$^{circ }hbox {C}$$ ∘ C . For Fe–Mg interdiffusion, each diffusion couple consisted of an ilmenite polycrystal and an oriented …
magnetite and hematite. Average grey levels are in the range of 152 for magnetite and between 186 and 218 for hematite (due to bireflectance). However, by stacking several images while rotating the polarizer, the average grey level difference between the maximum intensity for magnetite and the minimum intensity for hematite increases by about 36 %,
Hematite will leave a red to red-brown streak on the plate, while magnetite will leave a black streak. Ilmenite: Ilmenite is a dense, black metallic mineral that can be confused with metallic hematite, but again the two mineral's streak should serve to distinguish them. ... Ilmenite exhibits a black streak similar to that of magnetite, while ...
Ilmenite may contain significant isomorphic substitutions of Mg2+ and Mn2+ for both Fe2+, and probably forms solid solutions with both geikielite (Mg,Ti)2O3 and pyrophanite (Mn,Ti)2O3 end-members. Ilmenite commonly shows intergrowth with hematite and magnetite. The crystals are totally opaque and appear as thick tabular crystals or …
hematite and ilmenite belong to the trigonal system, they tend to form a coherent interface in solid transformation (Robinson et al. 2002); in contrast, rutile is tetragonal and magnetite cubic, so
The opaque minerals in ten lava flows of the Keweenawan series of Michigan were studied microscopically by the writer. The basaltic lavas, which range in thickness from 100 to 1,400 feet, contain ilmenite, magnetite, hematite, intergrowths of magnetite-ilmenite and ilmenite-hematite, copper sulfides, native copper, and pyrite.
Iron ore is an aggregate of several iron minerals, the main ones being hematite and magnetite.Iron ore and coal were and remain two key components of the Industrial Revolution, since the modern world depends on the mining and refining of iron ore for the integrity of its physical infrastructure: materials for construction, transportation and tools.
For example, Kletetschka and Stout (1998) found a region (Fig. 1) where the magnetization contrast was mainly due to RM carried by HISS mineralogy. In most cases, induced magnetization contrasts reflect the relative proportions of magnetite, which has a mass susceptibility three to four orders of magnitude larger than hematite and most of the …
The petrography and mineral chemistry of magnetite and hematite from igneous, metasedimentary, and sedimentary bedrock in the area of the Kiggavik unconformity-related uranium deposit, and from till covering the deposit were investigated using optical microscopy, scanning electron microscopy (SEM), electron probe micro-analyzer …
Section snippets Materials. Ilmenite (TiO 2 · FeO) and hematite (Fe 2 O 3) minerals were used in the tests, together with a rutile concentrate produced previously from the oil sands tailings by Lakefield Research Ltd.The latter will be referred to as LR Rutile in this paper. The ilmenite and hematite, originating from St. Urbain, Quebec (Canada) and Hoyt …
The assumptions are as follows: (1) the remanence at 10 K is from all three phases, hematite + ilmenite + magnetite; (2) the remanence below the Verwey transition and above 40 K (from ∼50 to 100 K) is from magnetite + hematite; and (3) the room temperature remanence after warming is from hematite. While this is an …
Earth's magnetic anomalies are commonly attributed to the presence of magnetite, hematite, titanomagnetite, and pyrrhotite minerals. Magnetite (Fe 3 O 4) shows strong …
Hematite Mineral Description. Hematite is an iron-oxide mineral of the Oxides and Hydroxides group, ... Very limited solid solutions have been reported with magnetite [Fe 3 O 4], ilmenite [FeTiO 3], and bixbyite [(Fe,Mn) 2 O 3]. The crystal system of hematite is hexagonal, but crystals appear in a wide variety of forms. Well crystallized forms ...
This study investigates magnetite exsolution in ilmenite from Fe-Ti oxide gabbro in the Xinjie intrusion, SW China. Exsolved magnetite lamellae in ilmenite contain nearly pure Fe 3 O 4 with ~1 wt% TiO 2.EBSD-based analyses indicate that the magnetite lamellae have close-packed oxygen planes and directions parallel to those in the host ilmenite with …
Magnetite, rutile needles, discrete pyrite and pyrrhotite are also present in AL20c. A late stage alteration with magnetite replacing hematite is commonly associated with sulfides. Magnetite is present also as elongate plates replacing some hematite. ... For the hematite-ilmenite system, this is a matter of some uncertainty, ...
Ore microaggregates are characterized by exsolution ((I) magnetite–ilmenite, (II) hematite–ilmenite) and replacement (martitization process) structures. The oxidizing …
The magnetism in ilmenite is of the same order as magnetite (Fe 3 O 4) but the magnetic susceptibility and magnetic saturation depends on whether the composition is low in titanium with a high amount of hematite or high in titanium containing a low amount of hematite. As titanium has no 3d electrons it is nonmagnetic; therefore, increased ...
A Microsoft ® Visual Basic software, called WinMIgob, has been developed for wet-chemical and electron-microprobe compositions of coexisting magnetite-ulvöspinel and ilmenite-hematite solid solutions to calculate the temperature (T, °C) and oxygen fugacity (fO 2) conditions of magmatic and metamorphic rocks.The program allows the users to …
In particular, the Åna-Sira anorthosite hosts numerous historic ilmenite- and magnetite-rich deposits (Korneliussen et al. 2000). Frøytlog is a historic ore deposit mined in the late …
ferromagrretic ordering in hematite is parallel to the [0001] axls. Ilmenite is also antiferromagnetic. The magnetic mo-ments, however, are aligned parallel to the [0001] axis (Ishikawa et al., 1985). In ilmenite, the Fe2+ atoms are ffil-Fig. l. Pseudobinary phase diagram of the hematite-ilmenite solid solution series (Burton and Davidson, 1988).
ILMENITE-HEMATITE-MAGNETITE RELATIONS INILMENITE-HEMATI. of Technology,Cambridge, Mass.AlsrnecrThe principal mode of occurrence of hematite …
Ilmenite, otherwise called manaccanite, is a titanium-iron oxide mineral with formula: FeTiO3. It is a noteworthy wellspring of titanium. Typically thick and tabular, its crystals …
The magnetite host contains ilmenite lamellae forming trellis and sandwich textures. In contrast to the requirement of the oxidation-exsolution model, the ilmenite lamellae are concentrated exclusively in the cores of the host crystals. The reverse host-guest relationship may also occur. Stages 4 and 5 are identical with thermally generated ...
Compositions [in terms of Ti/(Ti + Fe) at. %] of coexisting titanomagnetites (base) and ilmenite–hematite ss (top) re-equilibrated at 950°C in vacuo in the Fe–Ti–O system ... Consequently, the re-equilibrated 950°C assemblage displays higher magnetite and hematite contents; that is, a tie-line shifted to the left in Fig. 1.
Massif-type mafic intrusions (gabbro and anorthosite) are known for their considerable resources of vanadium-bearing iron–titanium oxide ores. Massive-type gabbroic and anorthosite rocks are frequently associated with magmatic rocks that have significant quantities of iron, titanium, and vanadium. The most promising intrusions that host Fe-Ti …
log f O 2 vs. T for several oxygen buffer reactions at 1 bar. MH D magnetite-hematite; RI D rutile-ilmenite; NNO D Ni-NiO; FMQ D quartz-fayalite-magnetite; WM D wüstite(Fe 0.947 O)-magnetite.