Image 54 of 156
Previous
Home
Next
25.0 Porphyritic hornblende andesite. Sierra Nevada, California. Black, rectangular hornblende phenocrysts, plus cream to white plagioclase phenocrysts, are scattered within the gray aphanitic groundmass. [Scale shows cm divisions.]
Image 54 of 156
Previous
Home
Next
![25.0 Porphyritic hornblende andesite. Sierra Nevada, California. Black, rectangular hornblende phenocrysts, plus cream to white plagioclase phenocrysts, are scattered within the gray aphanitic groundmass. [Scale shows cm divisions.]](../25.0.JPG)