Scientists Say: Inclusion | Science News for Students

Scientists Say: Inclusion

For those who study rocks, this is a material trapped inside a mineral as it forms
Mar 19, 2018 — 6:30 am EST
quartz inclusion
The bubble inside this piece of quartz is a type of inclusion. Inside the bubble is methane gas.
LucasFassari/Wikimedia Commons (CC BY-SA 4.0)

Inclusion (noun, “In-CLUE-shun”)

This word has a special meaning in mineralogy — or the study of minerals. To mineralogists, an inclusion is any material trapped inside a mineral as it forms. That material could be a rock trapped inside another rock. It can be a bug or a feather stuck in a glob of amber. It could be a bubble of gas trapped inside a gem. Inclusions can reveal important insights about the ancient world. For example, an insect trapped in amber can tell scientists a lot about what life was like when the amber formed — all the way down to a bug’s last meal. Climate scientists are interested in inclusions in other substances as well. They look for inclusions of gas bubbles in ancient ice cores or salts. Those bubbles can tell scientists what the Earth was like long ago.

In a sentence

Tiny inclusions in ancient rock salt helped scientists figure out how much oxygen filled Earth’s air 815 million years ago. 

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Power Words

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amber     Fossilized tree resin (not sap). Researchers think most of this gemstone likely comes from conifers, or evergreen trees that bear cones.

bug     The slang term for an insect. Sometimes it’s even used to refer to a germ.

climate     The weather conditions that typically exist in one area, in general, or over a long period.

core     Something — usually round-shaped — in the center of an object. (in geology) Earth’s innermost layer. Or, a long, tube-like sample drilled down into ice, soil or rock. Cores allow scientists to examine layers of sediment, dissolved chemicals, rock and fossils to see how the environment at one location changed through hundreds to thousands of years or more.

inclusion     (in geology) Something trapped inside a mineral.

insight     The ability to gain an accurate and deep understanding of a situation just by thinking about it, instead of working out a solution through experimentation.

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). (in physiology) The same chemicals that are needed by the body to make and feed tissues to maintain health.

mineralogy  The study of crystal-forming substances that make up rock, such as quartz, apatite or various carbonates.

oxygen     A gas that makes up about 21 percent of Earth's atmosphere. All animals and many microorganisms need oxygen to fuel their growth (and metabolism).

salt     A compound made by combining an acid with a base (in a reaction that also creates water). The ocean contains many different salts — collectively called “sea salt.” Common table salt is a made of sodium and chlorine.