1) Igneous rock
Found on
https://www.crosswordclues.com/clue/palagonite
Palagonite is an alteration product from the interaction of water with volcanic glass of chemical composition similar to basalt. Palagonite can also result from the interaction between water and basalt melt. The water flashes to steam on contact with the hot lava and the small fragments of lava react with the steam to form the light colored palago...
Found on
http://en.wikipedia.org/wiki/Palagonite
Palagonite is a fine dark red rock, usually found in thin layers between ancient flows of basaltic lava. It is really a weathered and oxidised basic tuff or ash-bed, composed of shreds of black volcanic glass, pumice and rock fragments.
Found on
http://www.probertencyclopaedia.com/browse/HP.HTM
No exact match found.
