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Igneous Rock Identification Lab
GEOS 110A: Earth & the Environment
This story map provides materials to help complete the GEOS 110 laboratory for identification of 15 common igneous rocks. The purpose of this lab is to...
- familiarize students with the concept of creating and testing multiple working hypotheses,
- develop a systematic and scientifically sound procedure with which to recognize an igneous rock, and
- identify a suite of unknown igneous rocks by first identifying textures, and then mineral composition.
The interactive 3-D models of the actual lab igneous rock samples were created using an ordinary camera and Agisoft Metashape Pro 3-D photogrammetry software. Using from 72 to 144 overlapping photos for each rock specimen, the software calculates the detailed topography of the rock using stereographic techniques and then overlays that 3-D geometry with a composite photographic texture of the rock's surface. The 3-D model is then imported into SketchFab, which creates the interactive environment that is embedded into this story map.
Unknown Igneous Rock #1 (I01)
Once 3-D models scroll into view, they will load and then you can interact with them (e.g., spin, zoom, etc.).
To see additional rocks, place cursor over THIS COLUMN OF TEXT and scroll down (if your cursor is over the interactive 3-D sample, scrolling will zoom in/out).
Unknown Igneous Rock #1 (I01):
- Please ignore the holes labeled with the #1 placemark when identifying this rock.
- Note the intermediate color of the fine-grained matrix labeled with the #2 placemark.
- Note the rectangular nature of the mineral crystal labeled with the #3 placemark.
Scroll down to see materials for the next rock.
MP4 video for Unknown Igneous Rock #1 (I01). Scroll down to see materials for the next rock.
Unknown Igneous Rock (I02)
Unknown Igneous Rock #2 (I02):
- Many of the rectangular mineral crystals on this rock have fine, parallel lines on their cleavage faces.
Scroll down to see materials for the next rock.
MP4 video for Unknown Igneous Rock #2 (I02). Scroll down to see materials for the next rock.
Unknown Igneous Rock #3 (I03)
Unknown Igneous Rock #3 (I03):
- Identifying the larger black crystals will help identify this rock.
- Note the intermediate color of the fine-grained matrix.
Scroll down to see materials for the next rock.
MP4 video for Unknown Igneous Rock #3 (I03). Scroll down to see materials for the next rock.
Unknown Igneous Rock #4 (I04)
Unknown Igneous Rock #4 (I04):
- Note the dark color of the fine-grained matrix (compare to Unknown Igneous Rocks #1 & 3).
Scroll down to see materials for the next rock.
MP4 video for Unknown Igneous Rock #4 (I04). Scroll down to see materials for the next rock.
Unknown Igneous Rock #5 (I05)
Unknown Igneous Rock #5 (I05):
- Be careful that you don't overestimate the amount of dark mineral in this rock.
Scroll down to see materials for the next rock.
MP4 video for Unknown Igneous Rock #5 (I05). Scroll down to see materials for the next rock.
Unknown Igneous Rock #6 (I06)
Unknown Igneous Rock #6 (I06):
- This rock is dominated by the many holes that are present. This tells us a great deal about the environment in which it formed.
Scroll down to see materials for the next rock.
MP4 video for Unknown Igneous Rock #6 (I06). Scroll down to see materials for the next rock.
Unknown Igneous Rock #7 (I07)
Unknown Igneous Rock #7 (I07):
- Are all minerals present in this rock of equal size?
Scroll down to see materials for the next rock.
MP4 video for Unknown Igneous Rock #7 (I07). Scroll down to see materials for the next rock.
Unknown Igneous Rock #8 (I08)
Unknown Igneous Rock #8 (I08):
- For the purposes of identifying this rock, you can ignore the small clear sanidine crystals in the tan matrix (although they certainly speak to the felsic nature of this rock).
Scroll down to see materials for the next rock.
MP4 video for Unknown Igneous Rock #8 (I08). Scroll down to see materials for the next rock.
Unknown Igneous Rock #9 (I09)
Unknown Igneous Rock #9 (I09):
- The large curved surfaces are classic examples of conchoidal fractures.
Scroll down to see materials for the next rock.
MP4 video for Unknown Igneous Rock #9 (I09). Scroll down to see materials for the next rock.
Unknown Igneous Rock #10 (I10)
Unknown Igneous Rock #10 (I10):
- The numerous holes in this rock help to trap air such that this rock would float if placed in water.
Scroll down to see materials for the next rock.
MP4 video for Unknown Igneous Rock #10 (I10). Scroll down to see materials for the next rock.
Unknown Igneous Rock #11 (I11)
Unknown Igneous Rock #11 (I11):
- This rock has characteristics of both igneous and sedimentary rocks.
- Some of the tan bits in this rock are actually pieces of Unknown Igneous Rock #10.
Scroll down to see materials for the next rock.
MP4 video for Unknown Igneous Rock #11 (I11). Scroll down to see materials for the next rock.
Unknown Igneous Rock #12 (I12)
Unknown Igneous Rock #12 (I12):
- This rock is comprised of almost 100% of one of the minerals that we studied.
- Green minerals are considered dark.
MP4 video for Unknown Igneous Rock #12 (I12). Scroll down to see materials for the next rock.