THE MINERAL PSEUDOBROOKITE

  • Chemical Formula: Fe2TiO5, Iron Titanium Oxide
  • Class: Oxides and Hydroxides
  • Uses: A very minor ore of titanium and as mineral specimens.
  • Specimens
Pseudobrookite is a rare and interesting mineral for collectors. It forms needle thin, acicular, crystals that form in sprays of several individuals. Its high luster, due to the titanium content, is rather nice and its rarity makes pseudobrookite an appreciated mineral in most anyone's collection. Pseudobrookite is associated with many interesting minerals such as pyroxenes, hornblende, tridymite, topaz, hematite and bixbyite. Most of the more popular of these assortments are found in cavities in rhyolitic rock and make for attractive and much sought after mineral specimens. Nice pseudobrookite specimens come from the Thomas Range in Utah.

PHYSICAL CHARACTERISTICS:

  • Color is dark black.
  • Luster is metallic to adamantine.
  • Transparency: Crystals are opaque.
  • Crystal System is monoclinic; 2/m
  • Crystal Habits include small acicular or thin prismatic crystals aggregated together in sprays of only a few individuals or singular. Also tabular.
  • Cleavage is indistinct in one direction.
  • Fracture is conchoidal.
  • Hardness is 6
  • Specific Gravity is 4.4 (average for metallic minerals)
  • Streak is brownish to reddish yellow.
  • Associated Minerals include spessartine, pyroxenes, hornblende, tridymite, hematite, bixbyite and topaz.
  • Notable Occurrences are limited to the Thomas Range, Utah and Piski, Transylvania, Romania.
  • Best Field Indicators are crystal habit, streak, associations and locality.
PSEUDOBROOKITE specimens:
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PSEUDOBROOKITE specimen pse-1
$ 35.00
Dims: 1.9" x 1.5" x 1.2"(4.8 x 3.8 x 3.0 cm)
Wt: 1.68 oz.(47.9 g)
Topaz Mountain, Thomas Range, Juab County, Utah, U.S.A.
This rather simple specimen contains a small but undamaged spray of radiating Pseudobrookite needles. The spray has a diameter of about 0.3"(0.8 cm) and consists of 20 to 30 crystals that range in size from 0.1 - 0.4 cm. They have a dark gray color and a vitreous, almost submetallic luster, and are opaque. This cluster rests in a small hollow in the rhyolitic host rock, along with many small but complete topaz crystals. These topaz crystals do not exceed 3 mm in length, but are transparent and clear, with a vitreous luster and definite crystal form that is difficult to see because of their size and heavy intergrowth. It is one of the better examples of Pseudobrookite that I have seen- usually they consist of single needles that are smaller than these, and often broken.
no photo
pse-1 ($ 35.00)
Topaz Mountain, Thomas Range, Juab County, Utah, U.S.A.
PSEUDOBROOKITE specimen pse-2
$ 45.00
Dims: 0.8" x 0.4" x 0.3" (2.0 x 1.0 x 0.8 cm) *Note: These dimensions do not include the display container
Wt: 1.68 oz.(47.9 g) (w/ container)
Thomas Range, Juab County, Utah, U.S.A.
This specimen simply consists of a cluster of about 10 monoclinic needlelike Pseudobrookite crystals. These crystals range in length from 0.1 - 0.8" (0.3 -2.0 cm) and are in generally good condition, though I believe that at least 3 of them are damaged and incomplete. The crystals have good form, nonetheless, and are easy to see when viewed against a pale background. They have the standard black color and what appears to be a submetallic-to-adamantine luster, and are, of course, opaque. The cluster was somehow removed from a piece of host rock and glued into a small hole that was drilled into the small face of a cork. The cork was then pushed into a small section of test tube that was shortened for the purpose. I have cleaned the glass tube, which was quite dirty, and replaced it over the specimen- the tube is rather old, and shows slight striations running down its sides that may interfere slightly with one's examination through it. These are the longest Pseudobrookite crystals that I have seen yet.
no photo
pse-2 ($ 45.00)
Thomas Range, Juab County, Utah, U.S.A.
 

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