Lecture 7 Flashcards Preview

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Flashcards in Lecture 7 Deck (20)
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1
Q

What are minerals?

A

Any naturally formed chemical substance having a definite chemical composition (but not fixed) and a characteristic crystal structure. (not all follow this exact definition)

2
Q

What place has the highest mineral diversity on earth?

A

The crust

3
Q

How many mineral types and varieties are there on earth?

A

4000 types, 10 000 varieties.

4
Q

What percentage of impurities will minerals accept (max) before changing?

A

40% (some will change after 1%)

5
Q

What can minerals not do?

A

Break into different mineral substances (ex: if you hit a block of table salt, it won’t break into Na and Cl)

6
Q

What are mineraloids and an example?

A

Substances with a definite chemical formula, but are amorphous (ions not arranged properly) NO CRYSTAL STRUCTURE-opal is an example (precipitation of silica forms an array of colours)

7
Q

What are organic minerals?

A

Minerals that require the action of certain organisms to form (ex: Whewellite requires precipitation of bacteria).

8
Q

What is the difference between organic sulphur and inorganic?

A

Inorganic- small crystals

Organic- Produced by bacteria, creates wide crystals

9
Q

Who was the first to classify minerals and how did he classify them?

A

Aristotle- Classified by colour, shape, weight, taste

10
Q

What are some examples of mineral imperfections?

A

Azurite-presents intergrowth (shared portions of crystal structure)
Tourmaline- in pure state, lacks colour. However, has some coloured areas created by different ions.

11
Q

Who invented the microscope and what did he discover?

A

Anthony Van something from the Netherlands. 1st discovery of cells

12
Q

How was the microscope transformed in the Early 90s?

A

Developed technology to increase the magnification of microscope to see crystal structure. Beam of electrons, and whatever is reflected back is observed

13
Q

How did the mineral Galena present under the microscope?

A

Repeating patters of light and dark coloured spots. Light=lead. Dark=sulphur. First direct observation of crystal structure in 1991.

14
Q

What shape will never be formed with geometrical packing?

A

Rounded shapes. Has to have a face and sides

15
Q

What are crystals?

A

Fundamental units of matter organization which have regular, repeating architecture (unit cell) reflecting packing of atoms

16
Q

What are some of the ideal geometrical packing shapes?

A

Tetrahedron, Cubical (1), Octaedron, Cubical (2)

17
Q

What is the crystal structure of diamond?

A

Carbon atoms situated in corners of tetrahedron-only creates covalent bonds (toughest in nature). Crystal structure is homogenous.

18
Q

How are diamonds formed?

A

High pressures-only form in upper mantle. Volcanic eruptions that raise molten matter to the surface can create diamonds on the surface.

19
Q

What is graphite’s crystal structure?

A

Unit cells of carbon atoms form a hexagon (not homogenous), covalent (plains) AND ionic bonds (between plains). Weak element parallel to plain.

20
Q

How is graphite formed?

A

Thermomaturation of dead organic animals-die at bottom of basin, burial process happens and trace elements are expelled (sulphur, phosphorous, nitrogen, oxygen , carbon).