21. The two oldest domes contain several percent phenocrysts ; the rest are essentially aphyric. 22. The calcium sulfate, anhydrite, was present as phenocrysts in the erupted tephra. 23. The basalt comprises phenocrysts of clinopyroxene and labradorite. 24. Phenocrysts include biotite, Si magmas, while higher Si magmas also contain sanidine.25. Some phenocrysts show evidence of a complex history. 26. Porphyritic dacites contain blocky highly zoned plagioclase phenocrysts and / or rounded corroded quartz phenocrysts. 27. Porphyritic dacites contain blocky highly zoned plagioclase phenocrysts and / or rounded corroded quartz phenocrysts . 28. Clinopyroxene ( augite ) and olivine are common as phenocrysts and in the tholeiitic basalt. 29. They contain glass, microliths and phenocrysts , and have a composition similar to phenocrysts. 30. They contain glass, microliths and phenocrysts, and have a composition similar to phenocrysts .
