http://www.geo.mtu.edu/KeweenawGeoheritage/Boulder_Garden/Boulder_Garden/Amygdules/Amygdules.html Amygdules http://www.geo.mtu.edu/KeweenawGeoheritage/Boulder_Garden/Boulder_Garden/Amygdules/Pages/Amygdaloid.html c7556a3b-9cc7-4520-b359-b755c239c488