微輝長斑岩為粗粒結晶之矽質玄武岩，具有等粒狀或明顯斑狀的岩石。微輝長斑岩又稱為微輝長岩或輝長岩，礦物成分之組合均以斜長石、普通輝石或鈦普通輝石與鈦鐵礦為主，其中斜長石的斑晶特別明顯，長度可達5公厘左右，舊稱粗粒玄武岩。但輝石結晶則呈微晶狀，故以微輝長斑岩命名。岩石呈暗灰色或灰黑色。已發現的地點有望安島的天台山、將軍澳嶼的船帆嶼、東吉嶼、金瓜仔嶼、狗沙仔嶼、白沙島通梁、屈爪嶼以及馬公本島之鎖港、山水、拱北山東北坡地下等地。微輝長斑岩在野外之特徵，如天台山、船帆嶼和屈爪嶼都具緊密而直立之板狀節理，常顯有數組縱橫或放射狀節理造成的特殊地景。這其中以東吉嶼之圓管狀微輝長斑岩體的「東吉之眼」及望安天台山「仙人腳印」最具盛名。本中心收藏的標本採集自望安天台山。
微輝長斑岩為粗粒結晶之矽質玄武岩，具有等粒狀或明顯斑狀的岩石。微輝長斑岩又稱為微輝長岩或輝長岩，礦物成分之組合均以斜長石、普通輝石或鈦普通輝石與鈦鐵礦為主，其中斜長石的斑晶特別明顯，長度可達5公厘左右，舊稱粗粒玄武岩。但輝石結晶則呈微晶狀，故以微輝長斑岩命名。岩石呈暗灰色或灰黑色。已發現的地點有望安島的天台山、將軍澳嶼的船帆嶼、東吉嶼、金瓜仔嶼、狗沙仔嶼、白沙島通梁、屈爪嶼以及馬公本島之鎖港、山水、拱北山東北坡地下等地。微輝長斑岩在野外之特徵，如天台山、船帆嶼和屈爪嶼都具緊密而直立之板狀節理，常顯有數組縱橫或放射狀節理造成的特殊地景。這其中以東吉嶼之圓管狀微輝長斑岩體的「東吉之眼」及望安天台山「仙人腳印」最具盛名。本中心收藏的標本採集自望安天台山。
Micro-gabbro porphyry is a coarse-grained crystalline siliceous basalt with iso-granularconspicuous spots. Also known as micro-gabbrogabbro, micro-gabbro porphyry is mainly composed of plagioclase, ordinary pyroxenetitanium ordinary pyroxeneilmenite. Among them, the phenocrysts of plagioclase (formerly known as coarse-grained basalt) are particularly obvious, with a length of about 5 mm, but pyroxene crystals are microcrystalline, so it is named after micro-gabbro porphyry. The rocks are dark graygray-black. The sites where the micro-gabbro porphyry has been found include Tiantai Hill in Wangan Islet, Chuanfanyu on Jiangjiyuenyu, Dongjiyu, Jinguazaiyu, Goushazaiyu, Tongliang on Paisha Islet, Quzhaoyu,Suogang, Shanshuithe northeastern slopes of Gongbeishan in the main island of Magong City. The micro-gabbro porphyry in the field, such as Tiantai Hill, ChuanfanyuQuzhaoyu, is characteristic of compactupright plate-like joints, often showing a special landscape caused by a series of verticalhorizontalradial joints. Among them, the "Eye of Dongji" with the circular tubular micro-gabbro porphyry in Dongjiyuthe "Footprints of Immortals" in Tiantai Hill of Wang-an Township are the most famous. The specimens collected by this center are from Tiantai Hill of Wang-an Township.
