Rocks, Minerals & Gemstones Quiz — 10 Free Questions

Question 1

What is the name for a hollow, roughly ball-shaped rock cavity, often dull on the outside, whose inner walls are lined with inward-pointing crystals, commonly of quartz, amethyst or calcite?

Question 2

Which hard rock is a dense form of near-pure silica that occurs as dark, glassy nodules inside chalk and some limestone, breaks with razor-sharp curved surfaces, and was the essential material for Stone Age blades, scrapers and arrowheads across much of the world?

Question 3

Which heavy, soft, bright metallic-grey mineral, lead sulfide, breaks into perfect cubes, is the world's chief ore of lead, and usually carries enough silver to be an important source of that metal too?

Question 4

What is the name for rock built up from loose particles, shells or dissolved matter that settle in layers and are then pressed and cemented together, typically forming flat beds, sometimes holding fossils, and covering most of the continents as a thin skin?

Question 5

Which gemstone is a hardened silica gel containing up to a tenth water, has no crystal structure, and in its precious form flashes patches of shifting spectral colour as it is turned, an effect caused by light bending around a regular stack of microscopic silica spheres?

Question 6

Which glassy, olive-green mineral, rich in magnesium and iron, is one of the main building blocks of the Earth's mantle and of dark rocks like basalt, and weathers quickly at the surface so it is rare in old sands?

Question 7

Which tough green ornamental stone is actually two different minerals of similar look, one a pyroxene called jadeite and the other an amphibole called nephrite, and has been carved for ritual objects, tools and jewellery for thousands of years?

Question 8

What is the name for the hot, molten or partly molten rock that lies beneath the Earth's surface, a mixture of liquid rock, dissolved gases and floating crystals that is less dense than the solid rock around it and so tends to rise?

Question 9

Which sedimentary rock is made largely of calcium carbonate, mostly from the shells and skeletons of sea creatures, fizzes when a drop of weak acid is placed on it, and is slowly dissolved by rainwater to form caves, sinkholes and the fluted grey pavements of upland Britain?

Question 10

Which bright green mineral, a copper carbonate, forms rounded, botryoidal masses with concentric light and dark green bands when sliced, and has been used since antiquity as a gemstone, an ornamental stone for tabletops and vases, and a green paint pigment?

📚 All Quizzes

Browse every category and see the full list of quizzes on BriskQuiz

→

About Rocks, Minerals & Gemstones

Almost everything solid under your feet is a rock, and every rock is a package of minerals. This quiz sorts out the difference and then works through eighty of them, along with the gemstones that are simply minerals rare and beautiful enough to wear. Each question describes something, a rock, a mineral, a gem, a physical property, a shaping process or one of the people who founded the science, and asks you to name it from four choices, then explains what it is, how it forms, how it is identified or used, and the history or misconception attached to it.

The first pack lays the foundations: what makes something a mineral rather than just a solid; what a rock is; the rock cycle that endlessly converts one kind into another; the three great families, born from a melt, built from sediment, or transformed in the solid state; the common members of each, from granite and basalt to sandstone, limestone, marble and slate; the most abundant minerals, quartz, feldspar and mica; and the hardness scale that runs from talc to diamond.

The second pack is the working mineralogy: the tests of cleavage, streak, lustre and specific gravity; the great ore minerals of iron, lead, copper and aluminium; rock-forming and everyday minerals such as calcite, gypsum, halite, graphite, talc, corundum and olivine; the volcanic glass obsidian and the floating rock pumice; the metamorphic trio gneiss, schist and quartzite; geodes, fossils and cave dripstones; the difference between weathering and erosion; and the vocabulary of veins, dikes, foliation and ores.

The third pack is the gem case: diamond and the four Cs; the carat and how it differs from the karat of gold; ruby and sapphire as the two faces of corundum; emerald, aquamarine and the other faces of beryl; amethyst, opal, jade, turquoise, pearl, amber, lapis lazuli, garnet, topaz and peridot; the month birthstones they attach to; the cursed Hope Diamond; the brilliant cut; and the diamond stand-in cubic zirconia. Because a specimen photograph often gives a mineral away to anyone who knows it, pictures are used only where they do not simply hand over the answer, and the most recognisable gems and minerals are left as text. Every figure has been checked, and the wording is kept plain.

Along the way the quiz settles the confusions people carry from school: that a rock and a mineral are not the same thing, one being a mixture and the other a single pure substance; that the 'lead' in a pencil is graphite and contains no lead at all; that fool's gold is pyrite and is lighter, harder and more brittle than the real thing; that weathering breaks rock down where it sits while erosion carries the pieces away; that a stalactite hangs from the ceiling and a stalagmite grows from the floor; that ruby and sapphire are the same mineral in different colours, as are emerald and aquamarine; that the carat which weighs a gem is a different word from the karat which grades gold; and that many historic crown 'rubies' are really spinel. Answers are always a single name chosen from four.