Week 4 Minerals & Rocks

Which of the following does NOT describe "minerals"?

• They are solids.

• They are natural subtances.

• Their atoms are arranged in an orderly pattern.

• They consist of rock pieces.

Answer explanation

Rocks are collections of minerals.

Which of the following chemical bonding can be present in minerals?

• Covalent bonding

• Ionic bonding

• Metallic bonding

• Plastic bonding

Answer explanation

Metallic bonding occurs in native elements (metals).

There is no such thing as plastic bonding in minerals.

What is mineral crystallisation?

• Atoms come together in proper arrangement to form solids

• Atoms separating from each other to form fluids

• Atoms come together in random arrangement to form solids

• Atoms come together to form dense liquids.

Answer explanation

Remember minerals are always in solid state so the atoms always come together and arranged in an orderly pattern.

Which of the following is the anion for oxides?

• O^2-

• O^3-

• O^-

• O²⁺

Ionic bonding always occurs between anions and ..............

• cations

• anions

• both cations and anions

• onions

Answer explanation

Anions are negative ions.

Cations are positive ions.

They attract each other to form the ionic bonding.

How does a gypsum mineral (CaSO₄.2H₂O) transform into an anhydrite mineral (CaSO₄)?

• By losing its water molecule

• By exposing it to high temperatures and pressures

• By exposing it to low temperatures and pressures

• By gaining more water molecules

Answer explanation

Anhydrite minerals are "dehydrated" gypsum meaning they have lost water molecules in the mineral structure.

Notice no H₂O molecules in anhydrite.

What is the name of a mineral containing calcium carbonate?

• Calcite

• Sandstone

• Dolomite

• Granite

Answer explanation

Sandstone and granite are examples of rocks, not minerals.

Dolomite is a carbonate mineral but contain magnesium (CaMg(CO₃)₂).

What is the principal anion of silicates?

• SiO₄^4-

• SiO₂

• Si⁴⁺

• O^2-

What is the name of this?

• Silicate tetrahedron

• Silicon oxygen pyramid

• Silicate pyramid

• Central silicate

Olivine is a mafic mineral. What does that say about olivine?

• Olivine is rich in magnesium and iron.

• Olivine is rich in silica.

• Olivine is green in colour.

• Olivine is rare.

Answer explanation

Mafic means high Mg and Fe content.