Chrysocolla

Chrysocolla is a blue or blue-green stone containing copper, silicon and water. It often has no orderly crystal structure: it usually occurs as glassy, opal-like or enamel-like masses whose crystals are too fine to see, or that are amorphous, which is why some sources count it as a mineraloid. It forms in the oxidised zone of copper deposits and, with a colour much like turquoise, has been used as an ornamental stone since antiquity.

Ornamental stone and jewellery: Carvings, beads and cabochons have been made since antiquity; it is easy to work. In silversmithing and goldsmithing it is often used in place of turquoise. Gem silica: Chalcedony with finely spread chrysocolla gives a vivid blue, translucent ornamental stone, best known from copper mines in Arizona; having the hardness of chalcedony (about 7), it is suited to jewellery. Copper ore: It is a minor ore of copper, but other minerals are the important sources of the metal.

It has a hardness of 2–4 on the Mohs scale. A fingernail cannot scratch it, but a steel knife can. Its specific gravity is 1.9–2.4 g/cm³.

Its best-known localities: Globe-Miami district, Arizona, USA; Nizhny Tagil, Ural Mountains, Russia; Timna Valley, Eilat, Israel; Katanga (Lubumbashi, Likasi), Democratic Republic of the Congo; Chuquicamata, Antofagasta, Chile.

Its colour is blue, sky blue or blue-green; it appears as crusts, grape-like lumps or vein fillings. Impure stone turns brownish black. Its hardness varies with the silica content, from about 2 to 4, and a knife scratches it. The silicified form (chrysocolla chalcedony) can be as hard as 7. Its specific gravity is low (about 1.9–2.4); its broken surface is smooth and shell-like (conchoidal). Used in place of turquoise: chrysocolla is often used in silversmithing and goldsmithing instead of turquoise; the two look alike in colour, but chrysocolla is a silicate and turquoise a phosphate.

On the “street to diamond” value ladder it sits on step 5 of nine: Ornamental stone. Its value depends on the vividness of the colour (pure sky blue is the most sought-after), the hardness of the stone and how well it takes a polish. Soft chrysocolla scratches and wears easily and so lasts poorly in jewellery; stones hardened by silica (chrysocolla chalcedony) are much more durable. “Gem silica”, chalcedony with finely and evenly spread vivid blue chrysocolla, is regarded as the most valuable variety of chalcedony. Any treatment applied to the stone should be disclosed by the seller.

Today crystal-therapy practitioners claim that chrysocolla is linked to the heart and throat chakras, calms, and brings emotional balance. Some news websites in Türkiye write that chrysocolla increases motivation and vitality, “rejuvenates”, and balances body and mind. The same articles say that the stone holds on to the feelings and thoughts of the people who touch it and therefore has to be “cleaned” regularly by leaving it in sunlight or burying it in the ground. There is no scientific evidence that chrysocolla gives vitality, calm or motivation, or that a stone holds on to people's feelings and thoughts. Chrysocolla contains copper: the stone should not be put in water to make a drinkable “elixir”, and its dust should not be breathed in. This section reports beliefs; it is not health information. There is no scientific evidence for these claims and no stone replaces medical treatment.

Chrysocolla contains copper. Holding or wearing polished stone is not a problem, but the dust from cutting, grinding and polishing should not be breathed in or swallowed. The stone should be worked wet, a dust mask worn, and the stone should not be put in water to make a drink.