Natural Stones

What’s in nature?

From elements to living things: what sits inside what in nature, and what comes from what? Tap the mineral, rock and other stone branches to open each stone’s path.

The base: elements

The building blocks of everything, living or not. 118 elements are known today; 94 occur in nature and 24 were made in the laboratory.

The three kinds of element (these are not below the elements; they are the elements):

Metalsiron, copper, gold, silver, mercury…
Non-metalsoxygen, carbon, nitrogen, sulfur…
Metalloidssilicon, arsenic, antimony…

Found pure in nature and counted as stones: Gold, Silver, Copper, Platinum, Bismuth, Sulfur, Diamond and Graphite (both pure carbon).

When elements combine, they form compounds (water, salt, quartz) and mixtures (air, soil, petroleum). About 99% of the human body is six elements: oxygen, carbon, hydrogen, nitrogen, calcium and phosphorus.

Solid, liquid and gas are states, not kinds: the same water becomes ice (a mineral) when it freezes and vapour when it is heated.

What about “fire, water, earth, air”?

The idea of “four elements” goes back to Empedocles around 450 BC and was abandoned in the late 1700s. Science today does not count them as elements:

  • Water is a compound: hydrogen + oxygen (H₂O).
  • Air is a mixture: 78% nitrogen, 21% oxygen, 0.9% argon…
  • Soil is a mixture: minerals, organic matter, water and air.
  • Fire is not a substance but a reaction: fuel burning rapidly with oxygen, giving off heat and light.

Living things

Cellular life falls into three great groups (“domains”). The system was proposed by Carl Woese and colleagues in 1990.

BacteriaSingle-celled, no cell nucleus.
ArchaeaSingle-celled, no nucleus; a group separate from bacteria.
EukaryotesAll living things whose cells have a nucleus.
Main branches of eukaryotes
Animalshumans, fish, insects, mussels, corals
FungiNot plants! More closely related to animals than to plants
Plantstrees, flowers, grasses, mosses
Othersbrown algae, amoebae and the like

The mushroom we eat is only the “fruiting body” of a fungus that lives underground.

On the edge: virusesThey have no cells and no metabolism of their own, but they can multiply inside a cell. Whether they count as living is debated.
Partnership: lichenA fungus living together with an alga or cyanobacterium. It may look like moss but it is not a plant; true mosses are plants.
What sits under what? Example: humans
EukaryotesAnimalsChordatesMammalsPrimatesGreat apesHomoHomo sapiens

Each step sits inside the one before: domain › kingdom › phylum › class › order › family › genus › species. Fungi and plants are separate kingdoms; neither sits under the other.

Non-living nature

From small to large: elements combine into ordered crystals to make minerals, and minerals come together to make rocks. Tap the branches to open each stone’s path.

Example: Amethyst
“Stone”: the everyday word that covers them all (the subject of this site)
  • Native metals: Gold, Silver, Copper, Platinum are both metals and minerals.
  • Ore minerals: most metals occur in nature not pure but in compounds: Hematite → iron, Chalcopyrite → copper, Galena → lead.
  • Ice is a mineral; liquid water is not. Mercury counts as a mineral as an exception, although it is liquid. Coal is a rock.
Liquids and gasesWater, air; petroleum (a liquid mixture of hydrocarbons) and natural gas (95% methane). These are neither minerals nor stones.

From living to non-living: what living things leave behind

Substances that living things make or leave behind become part of non-living nature. Some stay buried for millions of years and are transformed by heat and pressure.

Plant remains → peat → coal (a rock)
Plankton and algae → petroleum, natural gas (fossil fuels)
Tree resin → amber (fossil resin, not a mineral)
Tree trunks → petrified wood: minerals replace the wood
Shells, coral, microscopic sea life → limestone, chalk (rocks)
Oysters, mussels → pearl: not a mineral, because a living thing makes it
Soil is a mix of living and non-living. A typical soil holds:
5% organic matter; living things live in it too

Common mix-ups

Are fungi plants?No. Fungi are a kingdom of their own. Genetically they are closer to animals than to plants.
Is cork related to mushrooms?No. Cork is the bark of the cork oak tree, so it is a plant product. (In Turkish both are called “mantar”.)
Is petroleum a stone or a mineral?Neither. It is a liquid mixture formed from ancient plankton and algae. Coal, however, is a rock formed from plant remains.
Are metals and minerals the same?No. A metal is a kind of substance. Gold, silver, copper are minerals when found pure in nature, but most metals sit inside ore minerals as compounds, such as hematite.
Is lichen on rocks a moss?No. Lichen is a fungus living together with an alga or cyanobacterium; it is not a plant. True mosses are plants.
Are pearl, amber and coral minerals?No. Pearl, Amber, Coral are made by living things. They are called “stones” in everyday speech because they are used in jewellery.

Sources