#basalt

• Aphanite — An igneous rock (volcanic or subvolcanic) featuring an extremely fine-grained, microcrystalline, or glassy texture, where the component crystals are so small that they cannot be distinguished with the naked eye, requiring an optical microscope for identification. As an adjective, it describes the specific texture of these rocks (such as basalt or andesite), resulting from the rapid cooling of magma at the Earth's surface.
• Aphanitic — Pertaining to or having the characteristics of an aphanite; a term used to describe the texture of igneous rocks whose crystalline components are of microscopic or submicroscopic dimensions, making them indistinguishable to the naked eye. This extremely fine structural arrangement indicates a rapid solidification of magma or lava at or near the Earth's surface, a process that prevented the growth of large crystals.
• Amygdaloid — Resembling an almond in shape; ovoid and slightly flattened. In neuroanatomy, it describes the amigdaloid body (or cerebral amygdala), a deep nuclear structure essential for emotional processing. In mineralogy, it refers to the texture of a volcanic rock whose vesicles have been subsequently filled with secondary minerals, forming oval nodules.
• Augite — A mineral from the silicate class, belonging to the monoclinic pyroxene group, black, dark green, or brown, containing calcium, magnesium, iron, and aluminum. It is an essential and widespread component in many igneous rocks such as basalt, gabbro, or diabase.