Skip to main content
Geosciences LibreTexts

7.5: Activity 7D - Determining Textures and Compositions from Samples

  • Page ID
    14810
  • For this section, you will need igneous rock samples selected by your instructor. Locate these samples before you begin.

    1. Select the first sample designated by your instructor. Is this sample composed mainly of crystals, holes, glass, or clasts?

    1. Crystals

    1. Holes

    1. Glass

    1. Clasts

    1. What is the textural term for this sample?

    1. Crystalline, aphanitic

    1. Crystalline, phaneritic

    1. Vesicular

    1. Glassy

    1. Pyroclastic or fragmental

    1. What is the likely cooling history of this sample?

    1. This sample cooled as magma, slowly, in the intrusive cooling realm.

    1. This sample cooled as lava, quickly, in the intrusive cooling realm.

    1. This sample cooled as magma, slowly, in the extrusive cooling realm.

    1. This sample cooled as lava, quickly, in the extrusive cooling realm.

    1. What is the overall color of this rock?

    1. Green

    1. Dark - dark gray, green, black

    1. Gray

    1. Light - pink, white, beige

    1. What is the likely composition of this rock?

    1. Felsic

    1. Intermediate

    1. Mafic

    1. Ultramafic

    1. Identify this igneous rock by name:

    1. Select the next sample designated by your instructor. Is this sample composed mainly of crystals, holes, glass, or clasts?

    1. Crystals

    1. Holes

    1. Glass

    1. Clasts

    1. What is the textural term for this sample?

    1. Crystalline, aphanitic

    1. Crystalline, phaneritic

    1. Vesicular

    1. Glassy

    1. Pyroclastic or fragmental

    1. What is the likely cooling history of this sample?

    1. This sample cooled as magma, slowly, in the intrusive cooling realm.

    1. This sample cooled as lava, quickly, in the intrusive cooling realm.

    1. This sample cooled as magma, slowly, in the extrusive cooling realm.

    1. This sample cooled as lava, quickly, in the extrusive cooling realm.

    1. What is the overall color of this rock?

    1. Green

    1. Dark - dark gray, green, black

    1. Gray

    1. Light - pink, white, beige

    1. What is the likely composition of this rock?

    1. Felsic

    1. Intermediate

    1. Mafic

    1. Ultramafic

    1. Identify this igneous rock by name:

    • Was this article helpful?