Rocks and Minerals Basics

All the major concepts I need to know.

Front: What is the hardness value and mineral for Moh's 1?

Back: 1: Talc (soft, scratches easily with fingernail).

Front: What is the hardness value and mineral for Moh's 2?

Back: 2: Gypsum (scratches with fingernail ~2.5).

Front: What is the hardness value and mineral for Moh's 3?

Back: 3: Calcite (scratches with penny ~3).

Front: What is the hardness value and mineral for Moh's 4?

Back: 4: Fluorite.

Front: What is the hardness value and mineral for Moh's 5?

Back: 5: Apatite (scratches with glass ~5.5).

Front: What is the hardness value and mineral for Moh's 6?

Back: 6: Orthoclase Feldspar (scratches with steel ~6.5).

Front: What is the hardness value and mineral for Moh's 7?

Back: 7: Quartz.

Front: What is the hardness value and mineral for Moh's 8?

Back: 8: Topaz.

Front: What is the hardness value and mineral for Moh's 9?

Back: 9: Corundum.

Front: What is the hardness value and mineral for Moh's 10?

Back: 10: Diamond (hardest natural mineral).

Front: What common objects test Moh's hardness around 2.5, 3, 5.5, and 6.5?

Back: Fingernail (2.5), penny (3), glass (5.5), steel (6.5).

Front: Define luster

How light reflects off a mineral.

Front: What is metallic luster? Give an example.

Back: Shiny like metal; e.g., pyrite (fool's gold).

Front: What is vitreous luster? Give an example.

Back: Glassy shine; e.g., quartz.

Front: What is pearly luster? Give an example.

Back: Iridescent like pearl; e.g., mica.

Front: What is earthy luster? Give an example.

Back: Dull, soil-like; e.g., kaolinite.

Front: What is greasy luster? Give an example.

Back: Oily feel; e.g., talc.

Front: What is acicular habit? Give an example.

Back: Needle-like; e.g., actinolite.

Front: What is botryoidal habit? Give an example.

Back: Grape-like; e.g., malachite.

Front: What is cubic habit? Give an example.

Back: Cube-shaped; e.g., halite.

Front: What is dendritic habit? Give an example.

Back: Tree-like branching; e.g., manganese oxides.

Front: What is drusy habit? Give an example.

Back: Crusty crystal coating; e.g., quartz.

Front: What is massive habit? Give an example.

Back: No distinct shape; e.g., limestone.

Front: What is prismatic habit? Give an example.

Back: Elongated prism; e.g., tourmaline.

Front: What is bladed habit? Give an example.

Elongated and flattened, e.g, kyanite

Front: What is octahedral habit? Give an example.

12-sided mineral, e.g., garnet

Front: What is a doubly terminated habit? Give an example.

Crystals end on both sides, e.g., quartz

Front: What is a hopper habit?

resembles that of a pyramidal hopper container, e.g, Halite

Front: What is a twinning habit?

intergrown crystals, e.g., staurolite

Front: Define specific gravity/density/heft and categories with examples.

Back: Heaviness relative to water (density in g/cm³). Low (<2.5, light like sulfur or gypsum), Average (2.5-3.5, most like quartz), High (>3.5, heavy like galena or barite). Heft: Feels heavy/light for size.

Front: Define diaphaneity and types with examples.

Back: How light passes through. Transparent (clear, e.g., rock crystal quartz), Translucent (light passes but blurry, e.g., opal or milky quartz), Opaque (no light, e.g., pyrite).

Front: What is streak? Give an example.

Back: Color of mineral powder on streak plate; e.g., hematite (red), pyrite (black).

Front: What is cleavage? Give an example.

Back: Breaks along flat planes; e.g., mica (perfect 1 direction), calcite (3 directions rhombohedral).

Front: What is fracture? Give an example.

Back: Irregular break; e.g., conchoidal (smooth curved, like quartz).

Front: Mineral that effervesces with HCl?

Back: Carbonates like calcite, dolomite (fizz due to CO₂ release).

Front: Mineral with fluorescence? Example.

Back: Glows under UV; e.g., willemite (green glow).

Front: Magnetic mineral? Example.

Back: Attracts magnets; e.g., magnetite.

Front: Mineral with distinctive smell? Example.

Back: Rotten eggs; e.g., sulfur.

Front: Mineral with taste? Example.

Back: Salty; e.g., halite

Front: Mineral with double refraction? Example.

Back: Shows double image; e.g., calcite.

Front: Define tenacity and types with examples.

Back: Resistance to breaking. Brittle (shatters, e.g., quartz), Flexible (bends, e.g., mica), Elastic (springs back, e.g., mica), Malleable (hammers flat, e.g., gold), Sectile (cuts with knife, e.g., gypsum).

Front: What are nesosilicates? Example.

Back: Isolated tetrahedra; e.g., olivine (garnet also).

Front: What are sorosilicates? Example.

Back: Double tetrahedra; e.g., epidote.

Front: What are inosilicates? Examples.

Back: Chains; Single (pyroxene, e.g., augite), Double (amphibole, e.g., hornblende).

Front: What are cyclosilicates? Example.

Back: Rings; e.g., beryl.

Front: What are phyllosilicates? Example.

Back: Sheets; e.g., mica, talc.

Front: What are tectosilicates? Examples.

Back: 3D framework; e.g., quartz, feldspar.

Front: List polymorphs of CaCO₃.

Back: Aragonite (orthorhombic), Calcite (trigonal).

Front: List polymorphs of C.

Back: Diamond, Graphite.

Front: List polymorphs of KAlSi₃O₈.

Back: Orthoclase, Microcline.

Front: List polymorphs of Al₂SiO₅.

Back: Sillimanite, Andalusite, Kyanite.

Front: What is Bowen's Reaction Series discontinuous branch?

Back: Olivine → Pyroxene → Amphibole → Biotite → K-feldspar/Muscovite/Quartz (minerals change with cooling).

Front: What is Bowen's Reaction Series continuous branch?

Back: Plagioclase: Ca-rich (anorthite) to Na-rich (albite).

Front: Key processes in the rock cycle?

Back: Uplift, erosion, deposition, burial, compaction, cementation, heat & pressure, recrystallization, deformation, melting, solidification.

Front: Examples of depositional environments?

Back: Alluvial fan (mountain base), Delta/river/stream (fluvial), Lake (lacustrine), Swamp, Wind (aeolian), Floodplain, Beach/shallow marine/shelf, Deep marine.

Front: Low-grade metamorphic facies index minerals?

Back: Chlorite, muscovite.

Front: Medium-grade index minerals?

Back: Garnet, staurolite.

Front: High-grade index minerals?

Back: Kyanite, sillimanite.

Front: Blueschist/ecolgite formation?

Back: High pressure/low temp in subduction zones.

Front: Greenschist formation?

Back: Low-medium grade, green minerals like chlorite.

What are the 6 main crystal systems?

Cubic

Tetragonal

Orthorhombic

Monoclinic

Triclinic

Trigonal/Hexagonal

Cubic system

Highest symmetry — everything’s equal and square.

Has 4 threefold rotation axes (can be rotated 120° in multiple directions and look the same).

Examples: Halite (NaCl), Pyrite, Fluorite.

Tetragonal system

One axis (c) is longer or shorter → like a stretched cube.

1 fourfold rotation axis (rotate 90° around c-axis and it looks identical).

Examples: Zircon, Rutile, Apophyllite.

Orthorhombic

All right angles, but all sides are different lengths.

Has 3 twofold axes (one along each dimension).

Examples: Olivine, Aragonite, Topaz.

Monoclinic

One slanted angle → symmetry drops a lot.

Only 1 twofold rotation axis or mirror plane.

Examples: Gypsum, Orthoclase, Azurite.

Triclinic

Least symmetrical of all — no angles or sides equal.

Only has a single inversion point (flip it 180° and it looks the same).

Examples: Kyanite, Albite, Microcline.

Trigonal

Kind of like a tilted cube — still equal sides, but slanted angles.

Has a 3-fold rotation axis.

Examples: Calcite, Corundum, Tourmaline.

Hexagonal

Sides form a six-sided prism; one main axis (c) is unique.

Has 1 sixfold rotation axis (rotate 60° and it looks the same).

Examples: Quartz, Beryl, Apatite.