Rock Crystal

Rock crystal means as much as ice krystallos (Greek)

Occurrence
clear crystal can only form if all growth conditions remain constant over a long period of time. This is why clear mountain crystal is so rare.
Places of discovery of beautiful clear mountain crystals are mostly countries like Brazil, Arkansas/USA, Madagascar, Namibia.
Cloudy rock crystal can be found worldwide

Mineral class
Oxides
SiO2 + (Na,K,Cl,S,C). The formula SiO2

Mohs hardness: 7
density: 2,65
fissility: none, conchoidal fracture
Line colour: white
Transparency: transparent

Healing Effects
clear perception, neutrality, strengthens own point of view, clarity, purity