1.the commonest type of solidified lava; a dense dark gray fine-grained igneous rock composed chiefly of calcium-rich plagioclase feldspar and pyroxene.

• 最常见的凝固火山岩，是一种致密的深灰色火成岩，纹理细密，主要由富钙的斜长石和辉石组成。收藏指正