non silicates- carbonates

Question 1

identify the following carbonate:
habit:
- usually massive but isometric/cubic when fine grained 
colour:
- colourless/white
- white streak 
lustre:
-vitreous/pearly 
cleavage:
- three direction 
- perfect 
hardness:
- 3/4
additional properties:
- dissolves in HCL

Answer 1

dolomite

Question 2

what are the daignostic properties of dolomite?

Answer 2

• hardness 3/4
• perfect rhombahedral cleavage (three directions)
• dissolves in HCL

Question 3

which carbonates are you expected to know for the exam?

Answer 3

• dolomite
• calcite
• malachite
• azurite
• siderite
• aragonite

Question 4

identify the following carbonate: 
habit:
- subhedral bladed/isometric crystals 
aggregation:
- botryoidal 
colour:
- green 
streak:
- pale green streak
lustre:
-earthy/dull
hardness:
-1/2
cleavage:
- has 2 when well formed 
additional proeprties:
- dilutes in HCL

Answer 4

Malachite

Question 5

what are the diagnostic properties of a malachite specimine?

Answer 5

• hardness 1-2 (very doft compared to other green minerals)
• its very beautiful shade of green
• leaves a pale green streak (but beware chlorite does also)
• dilutes in hcl- spearates from other green streak minerals

Question 6

idnetify the following specimen:
habit:
- almost circular looking grains. isometric 
colour: 
-deep blue
lustire:
- ranges right from vitreous to dull 
hardness:
- 3/4
cleavage:
 - can have two poorly formed directions 
additional properties:
- dissolves in hcl

Answer 6

azurite

Question 7

azurite, kyanite, and sodalite are all blue minerals. how would you distinguish between the three?

Answer 7

• azurite will dissolve in HCL
• kyanite has three distinct cleavage directions
• sodalite has cleavage but commonly breaks in conchoidal fractures

Question 8

identify the following carbonate:
habit:
- blend of elongated and cubic crystals 
colour:
-distinct organgey brownish colour 
lustre:
-vitreous to pearly 
hardness:
-3/4
cleavege:
-h as one direction in theory

Answer 8

siderite

Question 9

what are the diagnostic properties of siderite?

Answer 9

• its colour and its dissolution in HCL

Question 10

identify the follwing carbonate mineral:
habit:
- has a VERY distinctive cubic habit when granular 
colour:
-white/transparent 
hardness:
- 3/4
cleavage:
- perfect in three direction 
- ~ 80 degree angle 
additional properties:
- dilutes in Hcl

Answer 10

calcite

Question 11

what are the diagnostic properties of calcite carbonate?

Answer 11

• dilutes in HCL

- three cleavage directions (none of the other carbonates have this)

Question 12

Dolomite and calcite have pretty much the SAME properties. How could you tell the two apart?

Answer 12

Dolomite has a much slower reaction with HCL, calcites is much more rapid