General Rocks Trivia Quiz

Answer: Chalk

Chalk is a sedimentary rock, a form of limestone composed of the mineral calcite, derived from the skeletons of planktonic algae called coccoliths. In its natural state, it is usually white or pale grey in colour, as seen in the chalk deposits that form the White Cliffs of Dover; it can have pigment added to it for what is more familiar to us in the classroom.

Answer: Marble

Marble starts out as limestone or dolomite, a rock made of calcium-magnesium carbonate. Exposed to heat, pressure, and aqueous solutions, it undergoes a process of metamorphosis, meaning simply that its grains are recrystallised. It gets its customary ...er...marbled...look from strands of calcite. Marble is used variously for sculpting, kitchen bench-tops or in the bathroom, and for paving or building.

Marbles like those in the picture are made from glass.

Answer: Sandstone

Quartz-bearing sandstone is one of the most common sedimentary rocks, and it can be changed into quartzite through metamorphism (the transformation of rocks into denser rocks) usually as a result of tectonic compression due to the collision of landmasses. Sandstone grains are held together by some type of 'mineral glue' (like iron oxide, silica, calcium or carbonate).

Layers of porous sandstone beneath the earth's surface allow it to serve as an aquifer for fluids such as water or oil, and this property makes it an important reservoir rock for petroleum or natural gas.

Answer: Extrusive

Dacite is an intermediate volcanic rock, similar to andesite but with more silica in its makeup, though low in alkali metal oxides. It forms when magma extrudes (flows out) during volcanic activity and is usually white to light grey in colour, lighter in colour than basalt. It makes a good aggregate rock in construction.

The picture is of a sausage machine extruding sausages!

Answer: Basalt

Basalt is the most common volcanic rock type. It is characterised by its fine grained texture, dark-grey to black colour and resistance to weathering and erosion. The way it is created lends itself to unique formations such as basalt plateaus, like the Moses Coulee canyon in Washington, lava tubes, such as the Organ Pipes National Park in Victoria, Australia, and columnar jointing, as found in the Devil's Tower in Wyoming, USA.

Bath salts in the picture provide a clue to basalt.

Answer: Plutonic

Norite is a coarse-grained mafic intrusive rock, high in magnesium and ferric oxides, and similar to a gabbro (the plutonic equivalent of basalt). It forms from the slow cooling of crystalized basaltic magma deep inside the Earth's crust. It is darker than granite and mostly black to dark green. Its composition means it is useful as cemetery markers, bench tops and jewellery.

Answer: Limestone

Limestone is a sedimentary rock important in cement and glass making, while crushed limestone is used as ballast in creating roads and railways. It is composed primarily of calcite, a ubiquitous rock-forming mineral whose chemical formula is CaCO3. In the case of the limestone found in caves, it is formed by evaporation; when a drop of water clinging to the stalactite evaporates instead of falling, any calcium carbonate in solution becomes part of the formation.

Answer: Serpentine

Serpentine gives its name to a group of minerals with the same formula - ((X)2-3(Y)2O5(OH)4). Beautiful examples of this stone include antigorite, chrysotile and lizardite. Serpentines are commonly slippery, translucent and patterned. Useful as a gemstone, and for architectural features like stairs, it also makes wonderful vases and ornaments.

Answer: Soapstone

Soapstone has been used since the Bronze Age for carving ornaments, pipes, effigies and for creating moulds with which to cast metal objects such as spearheads and knife blades. Because it's mostly composed of talc it carves easily. Soapstone comes in shades of grey, brown, bluish-grey or green.

Answer: True

'Pele's Hair' and 'Pele's Tears' are two of the most interesting types of lava produces as lava erupts and spatters over the surrounding area. Pele is the goddess of Hawaiian volcanoes and it is for this goddess that the formations are named. Pele's hair forms as mass of lava flies across through the air and separates into two or more clumps, connected by thin glassy strands.

The strands break easily and can be dangerous when handled.