Pebbles - which are actually rocks and minerals - are used to make nearly all the objects we use.
Scientists who specialise in what lies under the ground are called geologists, and their main job is to find the rocks and minerals that are used to manufacture all these everyday objects. Geologists are really explorers: when they go looking for minerals, they have to reconstruct the history of our planet and try to understand how it functions.
Aluminium for drink cans, copper for electricity cables, sand for windows and concrete, clay for bricks and tiles, rare earths for the loudspeakers in your mobile phone, kaolin for paper, cups and plates… all the mineral resources we need to make these everyday objects are in rocks extracted from the ground.
These mineral resources are metals, rocks, sand and gravel found in underground mines and open-cast quarries. Which ones can be found in which places depends on the nature of the subsurface - its geology in other words - and geologists are the people who identify them.