Clear Quartz

Quartz & Crystal Family

Clear quartz, traditionally called rock crystal, is the colorless transparent form of coarsely crystalline quartz, silicon dioxide. It commonly forms six-sided prisms capped by rhombohedral faces and may contain veils, fluid inclusions or other minerals.

Identity

Material or variety: Quartz
Scientific or material identity: Quartz
Classification: Natural mineral or mineral variety
Aliases or trade names: Rock crystal · Crystal quartz
Composition or formula: SiO₂
Crystal system or structure: Trigonal
Geological or manufacturing origin: Can form in more than one geological environment, or combines several materials.
Mohs hardness: 7
Specific gravity: 2.65

Origins

Brazil · Madagascar · Switzerland · USA

Appearance & optical properties

colorless transparent quartz with faint internal veils.

History & discovery

Ancient Greeks called transparent quartz krustallos, “ice,” because some writers believed it was water frozen permanently by extreme cold. Rock crystal was carved into vessels, seals and ornaments for centuries; the word quartz appeared in Georgius Agricola’s writing in 1529.

Uses & care

Common uses: Rock crystal is faceted or carved for jewelry, beads, seals and decorative vessels. Quartz also serves in optical components and electronic oscillators because of its optical and piezoelectric properties.
Handling and cleaning: Clean with warm soapy water and a soft brush. Avoid steam, ultrasonic cleaning, sudden heat and hard knocks when the crystal contains fractures or inclusions.

Jewellery

7 pieces of Clear Quartz jewellery. Learners earn each one in DigMyGem by learning words; until then it shows as a silhouette.

Crystal Sceptre
Sceptre
A medieval sceptre of the Lord Mayor of London, given by King Henry V in the 15th century. Its shaft is carved from rock crystal and mounted in gold and pearls, with a small jewelled crown at the top.
Winterglass Pendant
Pendant
An imagined pendant of flawless rock crystal, cut like a shard of winter ice. The clear stone is left open so light passes straight through it.
Cathedral Window Tiara
Tiara
An imagined tiara built of narrow arches, each filled with a flat pane of clear quartz. It borrows the crystal light of cathedral windows.
Lothair Crystal
Jewel
A circular disc of clear rock crystal engraved in the 9th century with eight scenes from the biblical story of Susanna, now in the British Museum. The crystal sits in a later gilt-copper frame.
Photo: Ashley Van Haeften, CC BY 2.0, via Wikimedia Commons
Saint-Denis Crystal
Jewel
A Carolingian rock-crystal intaglio of the crucifixion, made between 846 and 869, once kept in the treasury of the Abbey of Saint-Denis. It is now in the British Museum.
Sceptre of Scotland
Sceptre
A silver-gilt sceptre given by Pope Alexander VI to King James IV in 1494, it is part of the Honours of Scotland. Its finial ends in a globe of polished rock crystal beneath a gold orb and a large pearl.
Photo: Archibald Burns (1831-1880), Public domain, via Wikimedia Commons
Al-'Aziz rock crystal ewer
Jewel
A Fatimid ewer carved about the year 1000 from a single piece of rock crystal and inscribed for the caliph al-Aziz, kept in the Treasury of St Mark's Basilica in Venice. It is one of a rare group of seven medieval rock-crystal ewers.