What happens when you strike minerals with no cleavage with a rock hammer?

they fracture.

they bend.

they become magnetic.

they change color.

Although we have discussed x-ray identification of minerals and later in the course will discuss techniques that can be used to identify minerals with the optical microscope, it is still necessary to develop techniques that can be used in the laboratory and field where instrumentation like x-ray diffractometers or microscopes cannot be easily used.  Minerals have distinguishing physical properties that in most cases can be used to determine the identity of the mineral.  In this course, you will develop a systematic approach to using the physical properties of minerals as identifying tools.  If you follow this approach you should be able to identify most of the common minerals, or at the least be able to narrow the possibilities to only a few.  We will first discuss each of the physical properties that can be used, then develop a methodical approach to the identification of minerals using these physical properties.  Among the properties we will discuss are: crystal habit, cleavage, hardness, density, luster, streak, color, tenacity, magnetism, and taste.

Competition. interaction among organisms that compete for the same natural resource (food, shelter, water, space) in an ecosystem. predation. an interaction in which one organism kills another for food. predator. prey. symbiosis. mutualisum. commensalisum. parasitisum.

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