15. Sylvinite, a multicolored sedimentary rock made from a mixture of minerals, found all over the world
(By shakko, Wikimedia Commons)
16. Tectonites, metamorphic or tectonic deformed rocks, formed by recrystallization of minerals
(By Mikenorton, Wikimedia Commons)
17. Hyaloclastite, an igneous volcanic rock, formed by remnants of lava flowing through submarine or subglacial conditions
(By USGS, Wikimedia Commons)
18. Unakite, a rock found mostly in North America, formed from altered granite
(By Tom Harpel, Wikimedia Commons)
19. Laterite, a rust-color sedimentary rock found in tropical areas and used for building monuments
(By Phó Nháy, Wikimedia Commons)
20. Tiger’s Eye, a metamorphic rock used commonly as a cats-eye gemstone
