Brookite
A variety of Minerals
What is Brookite?
Brookite almost always appears together with Quartz; it's sometimes completely hidden in the Quartz mineral. It is a rare collector's mineral, particularly its variety called Arkansite, a black and opaque brookite found in Magnet Cave, Arkansas (USA). Only small fragments can sometimes be transparent. Cut crystals are very rare and mostly in private collections.
Etymology & Origins
It was named in 1825 by French mineralogist Armand Lévy for Henry James Brooke (1771–1857), an English crystallographer, mineralogist and wool trader.
Uses & Applications
Brookite is a mineral form of titanium dioxide, a substance which is important as a white paint pigment, food coloring, and ingredient in sunscreen. Collectors also like this mineral for its appealing rust-orange color. Small pieces are transparent and can be cut as gems for jewelry, although these are prized as they are rare.
Healing Properties
Brookite is said to be a high-vibration stone that may help in communication with angels and other spiritual guides. It has a powerful energy force that can help a person expand consciousness and provide better understanding of life. It can aid a person who is searching for their higher purpose in life and support them as they discover the opportunities and challenges that may unfold in the future.
Optical Properties
- Refractive Index
- 2.583-2.741
- Birefringence
- 0.117-0.158
- Pleochroism
- None
- Optical Character
- Biaxial positive
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Brookite Localities Map
See where Brookite is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
The Meaning
Brookite is a birthstone for the zodiac sign Cancer.
Associated Chakras
Key Characteristics
Characteristics of Brookite
Brookite is a brittle mineral, with a subconchoidal to irregular fracture and poor cleavage in one direction parallel to the c crystal axis and traces of cleavage in a direction perpendicular to both the a and the b crystal axes. Twinning is uncertain. The mineral has a Mohs hardness of 5 ⁄2 to 6, between apatite and feldspar. This is the same hardness as anatase and a little less than that of rutile (6 to 6 ⁄2). The specific gravity is 4.08 to 4.18, between that of anatase at 3.9 and rutile at 4.2.
Appearance of Brookite
Crystals typically tabular, elongated and striated parallel to their length. They may also be pyramidal, pseudo-hexagonal or prismatic. Brookite and rutile may grow together in an epitaxial relationship. Brookite is usually brown in color, or sometimes yellowish or reddish brown, or even black. Beautiful, deep red crystals (seen above-right) similar to pyrope and almandite garnet are also known. Brookite displays a submetallic luster. It is opaque to translucent, transparent in thin fragments and yellowish brown to dark brown in transmitted light.
Formation of Brookite
Brookite is an accessory mineral in alpine veins in gneiss and schist; it is also a common detrital mineral. Associated minerals include its polymorphs anatase and rutile, and also titanite, orthoclase, quartz, hematite, calcite, chlorite and muscovite. The type locality is Twll Maen Grisial, Fron Olau, Prenteg, Gwynedd, Wales. In 2004 brookite crystals were found in the Kharan, in Balochistan, Pakistan.
Composition of Brookite
The brookite structure is built up of distorted octahedra with a titanium ion at the center and oxygen ions at each of the six vertices. Each octahedron shares three edges with adjoining octahedra, forming an orthorhombic structure.
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Quick Facts
Physical Properties
- Color
- Brown, yellowish brown, reddish brown, dark brown to iron-black, yellowish brown to dark brown in transmitted light
- Hardness (Mohs)
- 5.5 - 6
- Density
- 4.133 g/cm³
- Streak
- White to greyish white or yellowish white
- Luster
- Vitreous, Adamantine, Sub-vitreous, Sub-metallic, Sub-adamantine
- Crystal System
- Orthorhombic
Chemical Properties
- Chemical Formula
- TiO2
- Elements
- O, Ti
Also Known As
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