玄武岩從外觀上可以區分為緻密狀、多孔狀與亞多孔狀三種玄武岩。多孔狀玄武岩,它氣孔多、比重較小、顏色較有變化。當玄武岩熔岩噴發時,因冷卻凝固的速率較快,其礦物的結晶顆粒較細,岩漿中氣體的逸散速度也來不及逸失,所以留下成群呈橢圓形的孔洞。常有方解石、霰石、玉髓、白雲石和褐鐵礦、菱鐵礦等次生礦物,慢慢充填在氣孔中而形成杏仁體或葡萄球狀的文石。本中心收藏的標本採集自馬公山水的多孔狀玄武岩。
玄武岩從外觀上可以區分為緻密狀、多孔狀與亞多孔狀三種玄武岩。多孔狀玄武岩,它氣孔多、比重較小、顏色較有變化。當玄武岩熔岩噴發時,因冷卻凝固的速率較快,其礦物的結晶顆粒較細,岩漿中氣體的逸散速度也來不及逸失,所以留下成群呈橢圓形的孔洞。常有方解石、霰石、玉髓、白雲石和褐鐵礦、菱鐵礦等次生礦物,慢慢充填在氣孔中而形成杏仁體或葡萄球狀的文石。本中心收藏的標本採集自馬公山水的多孔狀玄武岩。
In appearance, basalt can be divided into three types: dense, vesicularsub-vesicular. Vesicular basalt has more pores, smaller specific weightmore changes in color. When basalt lava erupts, the crystal grains of its minerals are finer due to the rapid coolingsolidification as a result, the gas in the lava cannot escape in time, thus leaving groups of oval holes. Secondary minerals such as calcite, aragonite, chalcedony, dolomite, limonitesiderite often slowly fill in the pores to form amygdalagrape-shaped aragonite. The specimens collected by this center are from the vesicular basalt of Shanshui Beach, Magong City.