apatite: A type of mineral, containing calcium and phosphate, which exists in some rocks and some types of fossils. It also is a component of bones, fish scales and the hard white enamel of teeth.
atom: The basic unit of a chemical element. Atoms are made up of a dense nucleus that contains positively charged protons and uncharged neutrons. The nucleus is orbited by a cloud of negatively charged electrons.
atomic: Having to do with atoms, the smallest possible unit that makes up a chemical element.
carbon: A chemical element that is the physical basis of all life on Earth. Carbon exists freely as graphite and diamond. It is an important part of coal, limestone and petroleum, and is capable of self-bonding, chemically, to form an enormous number of chemically, biologically and commercially important molecules.
chemical: A substance formed from two or more atoms that unite (bond) in a fixed proportion and structure. For example, water is a chemical made when two hydrogen atoms bond to one oxygen atom. Its chemical formula is H2O. Chemical also can be an adjective to describe properties of materials that are the result of various reactions between different compounds.
continent: (in geology) The huge land masses that sit upon tectonic plates. In modern times, there are six established geologic continents: North America, South America, Eurasia, Africa, Australia and Antarctica. In 2017, scientists also made the case for yet another: Zealandia.
crystal: (adj. crystalline) A solid consisting of a symmetrical, ordered, three-dimensional arrangement of atoms or molecules. It’s the organized structure taken by most minerals. Apatite, for example, forms six-sided crystals. The crystalline components of a rock are usually too small to be seen with the unaided eye.
decay: (for radioactive materials) The process whereby a radioactive isotope — which means a physically unstable form of some element — sheds energy and subatomic particles. In time, this shedding will transform the unstable element into a slightly different but stable element. For instance, uranium-238 (which is a radioactive, or unstable, isotope) decays to radium-222 (also a radioactive isotope), which decays to radon-222 (also radioactive), which decays to polonium-210 (also radioactive), which decays to lead-206 — which is stable. No further decay occurs. The rates of decay from one isotope to another can range from timeframes of less than a second to billions of years.
diamond: One of the hardest known substances and rarest gems on Earth. Diamonds form deep within the planet when carbon is compressed under incredibly strong pressure.
element: (in chemistry) Each of more than one hundred substances for which the smallest unit of each is a single atom. Examples include hydrogen, oxygen, carbon, lithium and uranium.
forge: (colloquially) to form one element from another under the intense heat and pressure inside stars.
lamproite: A type of potassium-rich, alkaline volcanic rock.
magma: The molten rock that resides under Earth’s crust. When it erupts from a volcano, this material is referred to as lava.
mantle: (in geology) The thick layer of the Earth beneath its outer crust. The mantle is semi-solid and generally divided into an upper and lower mantle.
mineral: Crystal-forming substances that make up rock, such as quartz, apatite or various carbonates. Most rocks contain several different minerals mish-mashed together. A mineral usually is solid and stable at room temperatures and has a specific formula, or recipe (with atoms occurring in certain proportions) and a specific crystalline structure (meaning that its atoms are organized in regular three-dimensional patterns).
molten: A word describing something that is melted, such as the liquid rock that makes up lava.
radioactive: An adjective that describes unstable elements, such as certain forms (isotopes) of uranium and plutonium. Such elements are said to be unstable because their nucleus sheds energy that is carried away by photons and/or and often one or more subatomic particles. This emission of energy is by a process known as radioactive decay.
rift: (v.) to break or split apart, such as a friendship. (in geology) The separation of a span of Earth’s surface along a geologic fault as a result of plate tectonics. (n.) The term for such a break or split.
rift zone: (in volcanology) An area where some volcano is splitting open, especially along its flanks. The rock here will be cracked and rather weak. That allows magma to push through it and to the surface. Once released from the rock, the lava will flow downhill, much as water would.
subatomic: Anything smaller than an atom, which is the smallest bit of matter that has all the properties of whatever chemical element it is (like hydrogen, iron or calcium).
supercontinent: Any of several large landmasses that divided in the ancient geologic past to form today’s continents. Notable examples of supercontinents include notably Pangaea, Gondwana and Laurasia.
tectonic: Surface activity on a large rocky body (such as a planet or moon) as liquid rock flows up to the surface where it solidifies, then slowly drifts atop molten rock, carrying surface features with it.
transmit: (n. transmission) To send or pass along.
trove: A collection of valuable things.
vertical: A term for the direction of a line or plane that runs up and down, as the vertical post for a streetlight does. It’s the opposite of horizontal, which would run parallel to the ground.
zircon: A gemstone that contains traces of the radioactive element uranium. It develops as a crystal that forms as magma (from deep inside Earth) begins to cool. Some of the oldest minerals surviving on the planet are crystals of zircon that are at least 4.2 billion years old. For perspective, Earth is only 4.56 billion years old.