Does biotite show cleavage or fracture?
Table of Contents
Does biotite show cleavage or fracture?
| Biotite | |
|---|---|
| Cleavage | Perfect on the {001} |
| Fracture | Micaceous |
| Tenacity | Brittle to flexible, elastic |
| Mohs scale hardness | 2.5–3.0 |
Does biotite have just 1 cleavage plane?
Important properties For biotite with low Fe-content (phlogopite), coloration is more subtle (clear, light browns and tans). Habit and cleavage – often appears as tabs or long skinny flakes which may be bent. It shows one excellent cleavage, depending on grain orientation. Rarely, it forms hexagonal crystals.
What is the fracture of biotite?
Biotite Mineral Data
| General Biotite Information | |
|---|---|
| Chemical Formula: | K(Mg,Fe++)3[AlSi3O10(OH,F)2 |
| Fracture: | Uneven – Flat surfaces (not cleavage) fractured in an uneven pattern. |
| Habit: | Lamellar – Thin laminae producing a lamellar structure. |
| Habit: | Micaceous – Platy texture with “flexible” plates. |
What can biotite be scratched by?
fingernail
Biotite has a hardness of 2.5, which means it can be scratched by a fingernail. Pyrite, on the other hand, has a hardness of 6.5.
How many cleavage planes does biotite have?
The mica minerals have one perfect cleavage that allows them to be broken into very thin sheets. This is very distinctive.
What is biotite cleavage?
Properties of Biotite It is a black mica with perfect cleavage and a vitreous luster on the cleavage faces. When biotite is separated into thin sheets, the sheets are flexible but will break upon severe bending. When held up to the light, the sheets are transparent to translucent with a brown, gray, or greenish color.
What is the hardness of biotite?
2.5 to 3
Biotite Physical Properties
| Chemical Classification | Dark mica |
|---|---|
| Cleavage | Basal, perfect |
| Mohs Hardness | 2.5 to 3 |
| Specific Gravity | 2.7 to 3.4 |
| Diagnostic Properties | Dark color, perfect cleavage |
What’s the second hardest mineral?
Corundum is the second hardest natural mineral known to science (1/4 the hardness of diamond). Gem varieties are sapphire and ruby.
Is biotite biaxial?
Optic Sign Some biotite may have a 2V of 0o, is sensibly uniaxial.
What property causes the mineral biotite to cleave into thin flat sheets?
The mineral has cubic cleavage.
Does biotite have low relief?
of biotite, in many rocks. Looks like a mica, but rather low relief, pale green colour and low or anomalous birefringence distinctive.
What cleavage angle does biotite mica have?
Biotite Optical Properties
| Property | Value |
|---|---|
| Cleavage | (001) perfect |
| Color/Pleochroism | Typically brown, brownish green or reddish brown |
| Optic Sign | Biaxial (-) |
| 2V | 0-25o |
What type of cleavage does biotite have?
| Physical Properties of Biotite | |
|---|---|
| Chemical Classification | Dark mica |
| Luster | Vitreous |
| Diaphaneity | Thin sheets are transparent to translucent, books are opaque. |
| Cleavage | Basal, perfect |
Is biotite resistant to chemical weathering?
biotite. It alters rather easily during chemical weathering and thus is rare in sediments and sedimentary rocks. One stage in the weathering of biotite has resulted in some confusion. During chemical weathering, biotite tends to lose its elasticity and become decolorized to silvery gray flakes.
Is anything harder than diamond?
The scientists found Q-carbon to be 60% harder than diamond-like carbon (a type of amorphous carbon with similar properties to diamond). This has led them to expect Q-carbon to be harder than diamond itself, although this still remains to be proven experimentally.
What mineral is stronger than diamond?
Although diamond undergoes a similar process, something about the structure of wurtzite boron nitride makes it nearly 80 per cent stronger after the process takes place, says study co-author Changfeng Chen at the University of Nevada, Las Vegas, an ability diamond does not have.
Does biotite have parallel extinction?
Biotite shows parallel extinction in cross polarized light, and has perfect cleavage in one direction. The biotite mineral shown here is exhibits bird’s eye texture during extinction, and the mineral is surrounded by quartz, muscovite, and feldspars.
Which minerals are biaxial?
Biaxial Minerals. All minerals that crystallize in the orthorhombic, monoclinic, or triclinic crystal systems are biaxial. Biaxial crystals have 2 optic axes, and this distinguishes biaxial crystals from uniaxial crystals.
