- Twelve andesite samples approximately 1" (3cm) in size
- Abundant phenocrysts in fine-grained matrix offer a great demonstration of igneous porphyry
- Perfect size for use in classroom identification labs and exercises, correlates well to Next Generation Science Standards Evidence Statements
- Texture and chemistry variation are excellent for students learning about differing cooling rates
- Specimen comes in clear labeled and barcoded bag for ideal storage
Andesite is an excellent example of porphyry in igneous rocks. The fine-grained felsic matrix contains larger, identifiable hornblende crystals, indicating two different rates of cooling. This sample can be used as a good introduction to igneous rock classification, and identifying minerals within igneous rocks.