Quartz occurs in both a crystalline and polycrystalline variety. Crystalline quartz consists of relatively large crystals that are usually visible to the unaided eye, while polycrystalline quartz is fine-grained and consists of masses of minute crystals.

Rock Crystal

Rock Crystal is a colourless, almost pure crystalline quartz. It occurs in cavities, geodes and in pegmatites, and also as rolled pebbles. Its name comes from the hardy mountain climbers of ancient Greece who first came upon it gleaming in hidden caves near Mount Olympus. They called it ‘krustallos,’ meaning ice, for they believed it to be water so frozen by the Gods as to be forever solid. Crystals of colourless quartz are abundant and show considerable variation in size, from crystals so minute that it would take about 4000 to make a gram, to gigantic crystals weighing more than 500g. Rock Crystal can be found in Brazil, USA, Russia, France, Myanmar and China.

• Rock Crystal jewellery is often given to mark a 15th Wedding Anniversary

View Rock Crystal Jewellery at Astley Clarke