Rock Identification Quiz: Igneous, Sedimentary, or Metamorphic
Quick, free rock identification test with photos-get instant results and learn as you go.
This rock identification quiz helps you tell igneous, sedimentary, and metamorphic rocks apart using clear photos. Use it to prep for a lab or hike, then try the geologic time scale quiz and a plate tectonics quiz to round out your earth science. If minerals interest you, the diamond knowledge quiz is a good next step.
Study Outcomes
- Identify Rock Families -
By the end, you'll distinguish igneous, sedimentary, and metamorphic rocks from images, confidently answering "what type of rock is this?" in seconds.
- Differentiate Rock Characteristics -
Learn to spot textures, colors, and patterns that set each rock kind apart when you identify rocks by picture.
- Apply Visual Identification Skills -
Practice classifying samples online using our rock identifier online quiz to boost accuracy and speed.
- Analyze Specimen Features -
Interpret visual cues like grain size, layering, and mineral composition to accurately identify rocks in any setting.
- Track and Compare Progress -
Measure your quiz score against fellow enthusiasts to monitor improvement and stay motivated to identify rocks online.
Cheat Sheet
- Mineral Composition & Texture -
When you ask "what type of rock is this?", start by examining grain size and mineralogy: igneous rocks range from fine-grained basalt to coarse-grained granite, with felsic types (>65% silica) being lighter and mafic types (<52% silica) darker. A useful mnemonic is "Felsic floats" to recall that granite appears pale and less dense than basalt (USGS Mineral Resources).
- Sedimentary Layers & Fossils -
Sedimentary rocks form in layers; clastic types like sandstone display visible grains and fossils, while chemical varieties like limestone may fizz with acid. Remember "G-C-O" (Clastic, Chemical, Organic) to categorize kinds of rocks with pictures and spot features such as shell fragments in limestone (American Geological Institute).
- Metamorphic Grade & Foliation -
Metamorphic rocks exhibit foliation and banding from heat and pressure; for example, shale transforms to slate, then schist, then gneiss as grade increases. Use the sequence mnemonic "Smart Students Get A's" (Slate, Schist, Gneiss, Amphibolite) to identify progressive textures (British Geological Survey).
- Hardness & Chemical Tests -
Field tests like the Mohs hardness scale and dilute HCl help distinguish quartz-rich sandstone (hardness ~7) from calcite-rich limestone (fizzes at hardness ~3). A handy trick is "Finger, Knife, Glass" to recall common hardness references: 2.5, 5.5, and 5.5 respectively (Smithsonian National Museum of Natural History).
- Visual Identification & Digital Tools -
Enhance your skill to identify rocks by picture using online rock identifier tools and mobile apps like Rockd or iRocks, which compare specimen photos against curated databases. Combining field observation with a rock identifier online boosts confidence in answering "what type of rock is this" and sharpens your geology prowess (University of Colorado Boulder).
