You have a geology lab practical next week, a unit test on earth science minerals, or a parent trying to explain why one rock sparkles and another doesn't — and the textbook chapter is dense, slow, and buried under diagrams you can't interpret without a guide.

**TLDR: Minerals** cuts straight to what you need. This short primer covers the five criteria that define a true mineral (and why ice, glass, and seashells don't always make the cut), the physical properties every geology lab mineral identification workflow depends on — hardness, luster, streak, cleavage, fracture, and density — and how to actually use a dichotomous identification key on an unknown specimen. It also explains the seven crystal systems, the major chemical mineral groups from silicates to sulfides, and why any of this matters beyond the exam room.

Written for US high school and early college students taking Earth Science, Physical Geology, or AP Environmental Science, this guide is short by design. No filler, no re-reading the same idea four ways. Every section leads with the one thing you need to take away, backs it up with concrete examples and worked numbers, and flags the misconceptions students most often get wrong.

If you need a focused earth science exam review for minerals before your next test or lab, pick this up and read it in one sitting.

• Define a mineral using the five-part geological criteria and distinguish minerals from rocks, glass, and synthetic materials.
• Apply the major physical properties — hardness, luster, streak, cleavage, fracture, density, and specific gravity — to identify unknown specimens.
• Use crystal systems and chemical composition to classify minerals into the major groups (silicates, carbonates, oxides, sulfides, sulfates, halides, native elements).
• Work through a standard mineral identification key the way a geologist or lab student does on an exam.
• Recognize why mineral identification matters in geology, resource exploration, and everyday materials.

1. 1. What Counts as a Mineral
   Defines a mineral by the five geological criteria and separates minerals from rocks, glass, ice, and biological materials.
2. 2. Physical Properties: The Geologist's Toolkit
   Walks through the diagnostic physical properties — hardness, luster, color, streak, cleavage, fracture, density — with how to test each in a lab.
3. 3. Crystal Systems and Internal Structure
   Explains how atomic arrangement produces crystal habits and the seven crystal systems, and why structure controls properties like cleavage.
4. 4. Chemical Classification: The Major Mineral Groups
   Organizes minerals by anion chemistry into silicates, carbonates, oxides, sulfides, sulfates, halides, and native elements, with key examples of each.
5. 5. Working Through an Identification Key
   Demonstrates the practical workflow of identifying an unknown mineral using a dichotomous key and worked specimen examples.
6. 6. Why Mineral Identification Matters
   Connects mineral ID to economic geology, environmental science, building materials, and the broader rock cycle.