63.1: Minerals

Here are 16 samples (or sample sets) of minerals that you will use to answer lab questions. Examine each sample in detail by zooming in and exploring its physical characteristics.

Sample Set A:

Sample A (all four) has the following properties:

Luster	Hardness	Color of streak	Cleavage?	Fracture?	Other properties
nonmetallic	3	white	Excellent; 3 directions, NOT at 90\(^{\circ}\) to each other	No	fizzes when HCl is applied

Sample B:

Sample B (both) has the following properties:

Luster	Hardness	Color of streak	Cleavage?	Fracture?	Other properties
metallic	2.5	gray to dark gray	3, at 90\(^{\circ}\)	No	Very dense (specific gravity = 7.5); stinks of hydrogen sulfide (rotten egg smell) if HCl is applied.

Sample set C:

Sample C1 (left) has the following properties:

Luster	Hardness	Color of streak	Cleavage?	Fracture?	Other properties
nonmetallic	1 – 6	brick red	No	No	(none)

Sample C2 (right) has the following properties:

Luster	Hardness	Color of streak	Cleavage?	Fracture?	Other properties
metallic	1 – 6	brick red	No	No	(none)

Sample D:

Sample D has the following properties:

Luster	Hardness	Color of streak	Cleavage?	Fracture?	Other properties
nonmetallic	7	(too hard to streak)	No	Brittle; may show parting	Dodecahedral crystals are distinctive.

Sample E:

Sample E (both) has the following properties:

Luster	Hardness	Color of streak	Cleavage?	Fracture?	Other properties
nonmetallic	2 – 2.5	white	1 (perfect)	No	can be split into thin, flexible sheets

Sample F:

Sample F has the following properties:

Luster	Hardness	Color of streak	Cleavage?	Fracture?	Other properties
nonmetallic	6.5	white	2, at 90\(^{\circ}\)	No	lamellae

Sample G:

Sample G (both) has the following properties:

Luster	Hardness	Color of streak	Cleavage?	Fracture?	Other properties
nonmetallic	2.5 – 3	gray-brown to white	1 (excellent)	No	can be split into thin, flexible sheets

Sample set H:

Sample H1 (left) has the following properties:

Luster	Hardness	Color of streak	Cleavage?	Fracture?	Other properties
nonmetallic	6-6.5	dark gray	Absent	No	magnetic

Sample H2 (middle) has the following properties:

Luster	Hardness	Color of streak	Cleavage?	Fracture?	Other properties
nonmetallic	6	white	2, at 90\(^{\circ}\)	No	lamellae

Sample H3 (right) has the following properties:

Luster	Hardness	Color of streak	Cleavage?	Fracture?	Other properties
metallic	2.5	gray to dark gray	3, at 90\(^{\circ}\)	No	Very dense (specific gravity = 7.5); stinks of hydrogen sulfide (rotten egg smell) if HCl is applied.

Sample I:

Sample I has the following properties:

Luster	Hardness	Color of streak	Cleavage?	Fracture?	Other properties
metallic	6-6.5	dark gray	absent	No	often forms cubes, sometimes with striations

Sample set J:

Sample J1 (left) has the following properties:

Luster	Hardness	Color of streak	Cleavage?	Fracture?	Other properties
nonmetallic	5.5-6	white to pale gray	Good. 2 planes, at about 60\(^{\circ}\)/120\(^{\circ}\) to each other	No	color dark gray to black; forms prisms.

Sample J2 (right) has the following properties:

Luster	Hardness	Color of streak	Cleavage?	Fracture?	Other properties
nonmetallic	5.5-6	white to pale gray	Moderate. 2 planes, at about 90\(^{\circ}\) to each other	No	color dark green to brown or black; forms short, 8-sided prisms

Sample K:

Sample K has the following properties:

Luster	Hardness	Color of streak	Cleavage?	Fracture?	Other properties
nonmetallic	2-5	white	absent	No	often forms dull or silky masses and asbestos (fibrous) forms.

Sample set L:

Sample L1 (left) has the following properties:

Luster	Hardness	Color of streak	Cleavage?	Fracture?	Other properties
nonmetallic	2	white	Good in 1 direction; poor in 2 more directions.	No	Forms tabular crystals, prisms, or blades. Transparent when pure; translucent when impurities are present.

Sample L2 (right) has the following properties:

Luster	Hardness	Color of streak	Cleavage?	Fracture?	Other properties
nonmetallic	1	white	Absent	No	Very soft. Feels soapy to the touch.

Sample M:

Sample M (all four) has the following properties:

Luster	Hardness	Color of streak	Cleavage?	Fracture?	Other properties
nonmetallic	7	None (too hard to streak)	Absent	Conchoidal	No reaction to HCl. Comes in many colors.

Sample set N:

Sample N1 (left) has the following properties:

Luster	Hardness	Color of streak	Cleavage?	Fracture?	Other properties
nonmetallic	2.5	white	Excellent: 3 planes at 90\(^{\circ}\) to each other (so it breaks into cubes)	No	Tastes salty.

Sample N2 (right) has the following properties:

Luster	Hardness	Color of streak	Cleavage?	Fracture?	Other properties
nonmetallic	4	white	Excellent: 4 planes	No	Often colorless (so it would appear black on a black background, like you see here), or translucent purple or green.

Sample O:

Sample O (both) has the following properties:

Luster	Hardness	Color of streak	Cleavage?	Fracture?	Other properties
nonmetallic	3.5-4	White	Excellent; 3 directions, NOT at 90\(^{\circ}\) to each other	none	Reaction to HCl occurs only if the mineral is powdered first.

Sample P:

Sample P has the following properties:

Luster	Hardness	Color of streak	Cleavage?	Fracture?	Other properties
metallic	1	Dark gray	Excellent in 1 direction	none	Greasy feel. Exceptionally soft.