Online Encyclopedia

Search over 40,000 articles from the original, classic Encyclopedia Britannica, 11th Edition.

ILMENITE

Online Encyclopedia

Originally appearing in Volume V14, Page 327 of the 1911 Encyclopedia Britannica.

» Make a correction to this article.
» Add information or comments to this article.

Encyclopedia Home :: I27-INV

Spread the word:

del.icio.us it!

ILMENITE , a See also:

MINERAL

mineral known also as titanic See also:

IRON [symbol Fe, atomic weight 55.85 (0=16)]

iron, formerly regarded as an iron and See also:

TITANIUM [symbol Ti, atomic weight 48.1 (0 = 16)]

titanium sesquioxide (Fe,Ti)203 isomoX-phous with See also:

HAEMATITE, or HEMATITE

haematite (Fe203), but now generally considered to be an iron titanate FeTiO3 isomorphous with pyrophanite (MnTiOa) and geikielite (MgTiO3). It crystallizes in the.parallell- ILOILO 327 faced helnihedral class of the See also:

RHOMBOHEDRAL

rhombohedral See also:

SYSTEM

system, thus having the same degree of symmetry as See also:

PHENACITE

phenacite and pyrophanite, but differing from that of haematite. The angles between the faces are very nearly the same as between the corresponding faces of haematite; but it is to be noted that the rhombohedral See also:

ANGLE (from the Lat. angulus, a corner, a diminutive, of which the primitive form, angus, does not occur in Latin; cognate are the Lat. angere, to compress into a bend or to strangle, and the Gr. ayKOS, a bend; both connected with the Aryan root ank-, to

angle (94° 29') of ilmenite is not intermediate between that of haematite (94° o') and of the artificially prepared crystals of titanium sesquioxide (92° 40'), which should be the See also:

case if the three substances were isomorphous. Analyses show wide See also:

variations in chemical See also:

composition, and there is a gradation from normal ilmenite FeTiO3 (with titanium dioxide 52.7, and ferrous See also:

OXIDE

oxide 47.3%) to titaniferous haematite and titaniferous See also:

MAGNETITE

magnetite. Frequently also, See also:

MAGNESIA

magnesia and manganous oxide are See also:

PRESENT

present in small amounts, the former reaching 16%. The See also:

formula (Fe,Mg)TiO3 is then analogous to those of geikielite and pyrophanite. Many analyses show the presence of TiO2 and (Fe,Mg)O in this ratio of 1:1, yet there is often an excess of ferric oxide to be accounted for; this may perhaps be explained by the See also:

REGULAR

regular intergrowth on a See also:

minute See also:

scale of. ilmenite with haematite, like the intergrowth of such substances as See also:

CALCITE

calcite and See also:

SODIUM [symbol Na, from Lat. natrium; atomic weight 23.00 (0=16)]

sodium nitrate, which are similar crystallographically but not chemically. In many of its See also:

EXTERNAL

external characters ilmenite is very similar to haematite; the crystals often have the same See also:

TABULAR

tabular or lamellar See also:

HABIT (through the French from Lat. habitus, from habere, to have, hold, or, in a reflective sense, to be in a certain condition; in many of the English senses the French use habitude, not habit)

habit; the twin-See also:

LAWS

laws are the same, giving rise to twin-lamellae and planes of parting parallel to the basal See also:

PLANE

plane and the See also:

PRIMITIVE

primitive rhombohedron; the See also:

COLOUR (Lat. color, connected with celare, to hide, the root meaning, therefore, being that of a covering)

colour is iron-See also:

black with a submetallic lustre; finally, the conchoidal fracture is the same in both minerals. Ilmenite has a black streak; it is opaque, but in very thin scales .sometimes transparent with a clove-See also:

brown colour. It is slightly magnetic, but without See also:

POLARITY (Lat. polaris, poles, pole)

polarity. The hardness is 51, and the specific gravity varies with the chemical composition from 4.3 to 5.o. Owing to the wide variations in composition, which even yet are not properly understood, several varieties of the mineral have been distinguished by See also:

SPECIAL

special names.

Crichtonite occurs as small and brilliant crystals of acute rhombohedral habit on See also:

QUARTZ

quartz at Le Bourg d'Oisans in See also:

DAUPHINE

Dauphine; it agrees closely in composition with the formula FeTiO3 and has a specific gravity of 4.7. Manaccanite (or Menaccanite) is a black sandy material, first found in 1791 in a stream at Manaccan near See also:

HELSTON

Helston in See also:

CORNWALL

Cornwall. Iserite, from Iserwiese in the Iser Mountains, Bohemia, is a similar See also:

sand, but containing some octahedral crystals, possibly of titaniferous magnetite. Washingtonite is found as large tabular crystals at See also:

Washington, See also:

CONNECTICUT

Connecticut. Uddevallite is from Uddevalla in See also:

Sweden. Picrotitanite or picroilmenite (Gr. snobs, " See also:

BITTER, KARL THEODORE FRANCIS (1867– )

bitter ") is the name given to varieties containing a considerable amount of magnesia. Other varieties are kibdelophane, hystatite, &c. The name ilmenite, proposed by A. T. Kupffer in 1827, is after the Ilmen Mountains in the See also:

SOUTHERN

southern Urals, whence come the best crystals of the mineral. The largest crystals, sometimes as much as 16 lb in See also:

WEIGHT

weight, are from Kragero and See also:

ARENDAL

Arendal in See also:

Norway. Ilmenite occurs, often in association with magnetite, in gneisses and See also:

SCHISTS (Gr. vxq'ecv, to split)

schists, sometimes forming beds of considerable extent, but of little or no economic value.

It is a See also:

COMMON

common See also:

ACCESSORY

accessory constituent of igneous rocks of all kinds, more especially basic rocks such as See also:

GABBRO

gabbro, See also:

DIABASE

diabase and See also:

BASALT

basalt. Iu these rocks it occurs as platy crystals, and is frequently re--presented by a See also:

white, opaque alteration product known as leucoxene. (L. J.

End of Article: ILMENITE

Additional information and Comments

There are no comments yet for this article.

» Add information or comments to this article.

Please link directly to this article:
Highlight the code below, right click, and select "copy." Then paste it into your website, email, or other HTML.

Site content, images, and layout Copyright © 2006 - Net Industries, worldwide.
Do not copy, download, transfer, or otherwise replicate the site content in whole or in part.

Links to articles and home page are always encouraged.

[back]
ILMENAU

[next]
ILOILQ