Rock Crystal
7Hardness (Mohs)
SiO₂Chemistry
16Known origins & mines
Water-clear quartz, the "master healer" of crystal lore. Historic sources include the Greek Alps (the name crystal derives from krystallos, "ice"), Brazil, Arkansas hot springs and Madagascar. Arkansas' Ouachita mountains remain America's premier collecting ground.
Known origins & mines
Jequitinhonha Crystal Belt · Brazil
Brazil supplies most world clear quartz; Jequitinhonha valley garimpos yield laser-clear singles up to metric sizes feeding both gem and ele…
Ouachita Crystal Diggings · United States
Hot Springs-area public mines let collectors pry water-clear quartz from clay seams of the Ouachitas — America's premier rock-crystal source…