You never know what you might find inside an agate. These minerals are formed in cavities left by gases trapped within volcanic rocks when they solidify. Later, water carrying silica in solution gets into the cavity and the silica gradually crystalises to become quartz. pic.twitter.com/7eIUdGYy6m

— New Scientist (@newscientist) January 26, 2021

@newscientist enviado por Fácil Nejo.