chain sillicates Flashcards
what are the two main types of chain silicates that you need to know for the exam?
- Amphibole
2. Pyroxene
identify the following chain sillicate: habit: - elongated/prismatic aggregation: - ranges from granular to massive colour: - black, dark green, dark brown - NO streak lustre: - vitreous to greasy hardness: - 5/6 cleavage: - two - perfect/good - ~120 degrees to one another
Hornblende
identify the following orthosilicate: habit: - acicular crystals - subhedral aggregation: - radial or granual depending on the sample colour: gree.n/greeny black - no streak hardness - 5/6 (scratched by quartz glass) lustre: - vitreous to silky cleavage: - two - perfect/good - 120 degrees to one another
actinolite
which are the two types of amphibloe (other then amphibole) that you need to be able to identify in the exam and how can you distinguish between them?
hornblende and actinolite. can distinguish as actinolite has acicular crystals and hornblende has elongated/prismatic crystals
what does the lab specimine of hornblende look like?
its a light grey rock with lump[s of bladed black crystals in it
the three types of amphiboles are: hornblende, amphibole and actinolite, how can you distinguish between the three once inditifying the shared characteristics?
- Amphibole is slightly softer with hardness 3/4 whereas hornblende and actinolite are 5/6
- actinolite has an acicular habit, the other two are elongated/ bladed
identify the following chain sillicate: habit: - elongated/bladed aggregation: - granular colour: - black/very dark grey hardness: -3/4 lustre: - vitreous cleavage: - 2 directions - good 120 degrees
amphibole - can tell as its slightly softer than the other two amphibole examples
amphiboles and pyroxenes are two chain silicates, what is the best way to distinguish between them?
pyroxene has two cleavage directions near 90 degrees to one another, hornblende has two cleavage directions near 120 degrees to one another
there are two pyroxenoids that you need to know for the exam. name them
- Wollastonite
2. Rhonodonite
how would you be able to distinguish the rhonodonite specimine in the exam?
its rosy pink with black streaks and kinda resembles a salt lamp
how would you distinguish a wollastonite specimine in the exam?
its olive green and slightly grainy but isnt like olivine, has black and brown streaks