Chapter 3. Igneous Rocks
Lab 4 Activity
Overview
For Lab 4 you will identify the 11 igneous rock samples in your lab kit based on observations of their colour, texture, and mineral content. The samples include the following igneous rocks:
| Andesite | Gabbro | Pegmatite | Pumice |
| Basalt (x2) | Granite | Peridotite | Rhyolite |
| Diorite | Obsidian |
Samples to Use for Lab 4
Use the samples with “RIg” in the sample number. They are numbered 230RIg through 330RIg. You will also need the Lab 4 worksheet that came with your lab materials.
What to Do Next
Use the Lab 4 worksheet (Figure 3.9) to record your observations and guide you through the identification process for each igneous rock in your set.
Refer to Figures 3.10 to 3.12 in the Reference Tools for Igneous Rocks section of this lab manual to help you match your observations with a name.
REMEMBER: Where appropriate, include textures like amygdaloidal, porphyritic, and vesicular when you name a sample. (e.g., vesicular basalt)
