Speleothem is a hypernym of coralloid.

As nouns the difference between speleothem and coralloid

is that speleothem is (geology) any mineral deposited in a cave by the action of water while coralloid is a small node of calcite, aragonite or gypsum that forms on surfaces in caves, especially limestone caves.

As an adjective coralloid is

having the shape or form of coral.