a small gas pocket, usually found in volcanic rock, partly or completely filled with a mineral, esp. a zeolite, calcite, or quartz
sometimes called amyg′dale·
Origin of amygdule; from Classical Latin amygdala, almond: from the typical shape
A small gas bubble in igneous, especially volcanic, rock filled with secondary minerals such as zeolite, calcite, or quartz.
Origin of amygduleLatin amygdala, almond (from its shape); see amygdala + (nod)ule.