Biotite!! Click on this link to get AWESOME Biotite information. It's sweet. Hit glogs when you get there and then click on the Biotite Blog. Hope to see you there!

Biotite is in a group called Mica. It is a very flexible mineral. if you bend it, it can go back to its original shape. To figure out how old the mineral is you can look at its radioactive elements. Biotite can be found in Russia, Sicily, Ontario, and Sudbury.

Group Name: silicate
Chemical Composition: KMg2.5Fe2+0.5AlSi3O10(OH)1.75F0.25
Crystal Shape: Varies
Cleavage- Perfect basal
Luster- Pearly, glossy, and vitreous.
How it forms: Biotite forms in both igneous and metamorphic rock.
Fracture- Uneven
When trying to identifying Biotite you notice that it has a dark color, and it has perfect cleavage.
Transparency- crystals are transparent to translucent
The colors Biotite are usually dark brown, dark green, or black.

Biotite doesn't have very many uses, although its main use is one we see almost every day. Biotite is found in concrete and other construction materials.

Hardness: 2.55-3

Streaks on Biotite are usually white to grey.

Specific Gravity: 2.7 - 3.3

~The color of Biotite is mostly black or brown.

~Biotite has layered structures.

~The streak of Biotite is white.

~The hardness is 2.5

~It is a common rocl forming mineral.

Terms to Know:
  • Metamorphic Rocks- A rock once and formed into a another rock by pressure, heat, or something else without going through a liquid state.
  • Igneous Rocks- Rocks from becoming solid and cool. Can be from inside the earth or from a volcano.
  • Transparent - clear
  • Translucent - Can see through, but it looks blurry on the other side. For example a frosted window is translucent, you can see through it but its blurry.

external image Fig.P011A-Biotite.jpg