When there are no impurities, pure quartz is water-clear and often referred to as “rock crystal”. Impurities can give transparent quartz beautiful hues, such as yellowish citrine (iron ...

(2) The multiple medieval Christian interpretations honor the miraculous nature of God and are reinforced by the relic’s visibility within this ideologically charged rock crystal. Although the clear ...

Evidence for the use of rock crystal - a rare type of perfectly transparent quartz which forms in large hexagonal gems - has occasionally been found at prehistoric sites in the British Isles, but ...