chain sillicates

Question 1

what are the two main types of chain silicates that you need to know for the exam?

Answer 1

1. Amphibole

2. Pyroxene

Question 2

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

Answer 2

Hornblende

Question 3

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

Answer 3

actinolite

Question 4

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?

Answer 4

hornblende and actinolite. can distinguish as actinolite has acicular crystals and hornblende has elongated/prismatic crystals

Question 5

what does the lab specimine of hornblende look like?

Answer 5

its a light grey rock with lump[s of bladed black crystals in it

Question 6

the three types of amphiboles are: hornblende, amphibole and actinolite, how can you distinguish between the three once inditifying the shared characteristics?

Answer 6

1. Amphibole is slightly softer with hardness 3/4 whereas hornblende and actinolite are 5/6
2. actinolite has an acicular habit, the other two are elongated/ bladed

Question 7

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

Answer 7

amphibole - can tell as its slightly softer than the other two amphibole examples

Question 8

amphiboles and pyroxenes are two chain silicates, what is the best way to distinguish between them?

Answer 8

pyroxene has two cleavage directions near 90 degrees to one another, hornblende has two cleavage directions near 120 degrees to one another

Question 9

there are two pyroxenoids that you need to know for the exam. name them

Answer 9

1. Wollastonite

2. Rhonodonite

Question 10

how would you be able to distinguish the rhonodonite specimine in the exam?

Answer 10

its rosy pink with black streaks and kinda resembles a salt lamp

Question 11

how would you distinguish a wollastonite specimine in the exam?

Answer 11

its olive green and slightly grainy but isnt like olivine, has black and brown streaks