Amygdaloid n. (Min.) A variety of trap or basaltic rock, containing small cavities, occupied, wholly or in part, by nodules or geodes of different minerals, esp. agates, quartz, calcite, and the zeolites. When the imbedded minerals are detached or removed by decomposition, it is porous, like lava.
adjective
Amygdaloidal, Amygdaloid adj.
1.
Almond-shaped.
2.
Pertaining to, or having the nature of, the rock amygdaloid.
... wings of Fancy, and once more I stand upon thy shores! Over thy broad savannahs I spur my noble steed, whose joyous neigh tells that he too is inspired by the scene. I rest under the shade of the corozo palm, and quaff the wine of the acrocomia. I climb thy mountains of amygdaloid and porphyry— thy crags of quartz, that yield the white silver and the yellow gold. I cross thy fields of lava, rugged in outline, and yet more rugged with their coverture of strange vegetable forms—acacias and cactus, yuccas and zamias. I traverse thy table-plains ... — The War Trail - The Hunt of the Wild Horse • Mayne Reid
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