Mica is the name given to a group of silicate minerals that have silicon and oxygen as their two major components. The Mica family of minerals includes several variations based on chemical composition and characteristics. Three out of at least eleven are mentioned under out of the common variations.
- Biotite
- muscovite
- boromuscovite
The group formula including all member minerals:
K(Mg,Fe2+)3(Al,Fe3+)[(Al,Si)3O10](OH,F)2
Mica is a metamorphic mineral. The many variations come from the diverse ways it formed. Mica formations are associated with volcanoes and hydrothermal vents.
The most easily recognizable characteristic are the thin crystal layers. With many micas the sheets peel off in thin transparent layers due to mica’s perfect cleavage.
The crystal structure is monoclinic with a somewhat hexagonal crystal shape. These two characteristics are due to the structure of the atoms that make up the mica group.
Mica also has a brilliant shininess that glitters and sparkles. In fact the name mica is believed to have come from the Latin word micare which means “to shine.” Mica is responsible for the flashes of light in composite rocks such as granite, gneiss, and slate.
Mica is often used as an insulator in electrical applications, but it is also valued for collections and artistic applications.
You will normally find the mica like this in a stone, and not in a big sized mineral as the photos above, so here is what you will be looking for at the stone at gz. (Example photo under, not from gz)
To log this cache.
To get to log this cache you will have to read the cache text and visit the coordinates given. After that you will have to answer the questions which are related to the text and the coordinates given.
When answers are collected, send them to CO for verification. I will accept answers sent via email or through the Message Centre.
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Please do not include pictures in your log that may answer the questions.
Questions
1. Answer the questions under by visiting the Coordinates.
A. How can you easily identify the Mica/Muscovite? Also describe the Mica/Muscovite at GZ with its shape and colour?
B. The coordinates have lead you to The Parrot head. Have a look around the statue, how much percentage of the mica/muscovite would you say the stone contains?
C. What average size are the black crystals that you find?
D. At the front part of the stone with the plaque you can read: Parrot head”, do you think there are more spots to find at this part of the stone than the other three sides?
2. It’s voluntary to post a photo in your online log. Without revealing any answers!
