Which of the following is the most stable and abundant form of silica in nature?
Analysis & Theory
Quartz is the most common and stable polymorph of silica under Earth's surface conditions.
Which silica mineral forms at high temperatures and low pressures, often found in volcanic rocks?
Analysis & Theory
Tridymite is a high-temperature polymorph of silica found in volcanic environments.
Cristobalite is a polymorph of silica that forms at:
A
High temperature and low pressure
B
Low temperature and high pressure
C
Surface weathering conditions
D
Deep marine environments
Analysis & Theory
Cristobalite forms at high temperatures and low pressures and is often seen in volcanic glasses.
Which of the following is a fibrous and microcrystalline variety of silica?
Analysis & Theory
Chalcedony is a compact, microcrystalline variety of silica composed of fine intergrowths of quartz and moganite.
Which silica mineral is amorphous and hydrated, often used in jewelry?
Analysis & Theory
Opal is an amorphous, hydrated form of silica that often displays beautiful color play.
Which high-pressure polymorph of silica is commonly formed during meteorite impacts?
Analysis & Theory
Coesite forms under high-pressure conditions such as those present during meteorite impacts.
Stishovite is unique among silica minerals because it:
B
Has a cubic crystal structure
C
Is extremely dense and forms under ultra-high pressure
Analysis & Theory
Stishovite is a very dense, high-pressure polymorph of silica found in impact craters.
Which of the following silica forms is used extensively in glass and ceramic industries?
Analysis & Theory
Quartz, especially in powdered form (silica sand), is widely used in glass and ceramic manufacturing.
Which silica polymorph is stable only at very high pressures and is rare on Earth's surface?
Analysis & Theory
Stishovite is a rare, high-pressure form of silica that only occurs naturally in meteorite impact sites.
Which variety of silica is known for its colorful and banded appearance?
Analysis & Theory
Agate is a colorful, banded form of chalcedony, a microcrystalline variety of silica.