Rhyolite is an extrusive acidic rock with a porphyritic structure. The phenocrysts are mainly quartz and alkali feldspar and occasionally plagioclase. The matrix is dense cryptocrystalline glassy materials. Rhyolite is widely distributed in many provinces in eastern China and forms unique landforms. Typical examples are the Yandangshan and Linhai landscapes in Zhejiang Province, Baishuiyang in Fujian Province, Mirs Bay in Shenzhen, Guangdong Province and the Hong Kong Geopark in Sai Kung.