FAQ Gems

Ametrine is a trade name for a naturally ocuring combination in Quartz of purple Amethyst and yellow Citrine in one stone. The color variety is due to different degrees of oxidation of the mineral’s Iron content as a result of temperature variations within the mineral during formation. Origins are Bolivia and Brazil. Over the past two decades, Ametrine has become an extremely scarce mineral.

Pictured: Ametrine pendant by CADEAUX JEWELRY, gem sculpted by Swiss-Australian artist Bruno Moser.

Black Jade is a common name for Augite, an opaque jet-black and shiny mineral that is mainly of eruptive origin. Its greenish-white cousin that is mainly found in Burma is the more well-known variety, revered as Jade, Imperial Jade or Jadeite, which owes its color to its Chromium content. Main origins are Burma (green Jade), China, Guatemala and Mexico. (Schumann)

Pictured: CADEAUX JEWELRY Cult Il Magnifico rings in 18Kt gold, skulls carved from Black Jade (left), Chalcedony and Turquoise.

Carat is a unit of weight measure used mainly for cut and polished or carved gems. 1 Carat is equivalent to 200 milligrams or 0.2 grams. Carat as a weight measure should not be confused with the indicator of an alloy’s gold content, say 18 Karat, normally spelled Karat with a K for easier distinction.

Chalcedony is a designation that in a wider classification groups together micro-crystallic structured Quartzes (Silicon Dioxides) comprising Carneol, Jasper, Chrysoprase, Jasper, while a more narrow definition of Chalcedony covers only the white-grayish and bluish translucent kind. Chalcedony is popular for carvings as well as beads. Main origins are Brazil, India and Madagascar. (Schumann)

Pictured: CADEAUX JEWELRY Cult Il Magnifico rings in 18Kt gold, skulls carved from Chalcedony (below), Black Jade and Turquoise.

Dendritic Quartz (Silicon Dioxyde) is a white-grayish and translucent Chalcedony with a dark-brown matrix. The matrix-patterns resemble trees or ferns, hence the reference Dendrite or dendritic meaning tree-like, derived from dendron, or “tree” (Greek). The dark-brown patterns are made up of Iron secretions and Manganese oxides from neighboring rocks, which have oozed into fissures between thin Chalcedony layers. Main origin is Brazil (Rio Grande do Sul), followed by USA and India. (Schumann)

Gemstones and gem raw material are often subjectet to treatments. While some treatments are common and have been practiced for hundreds of years, others are more recent and often more controverstial. CIBJO – The World Jewellery Confederation during its Munich conference in February 2010 set that the following types of treatment be mentioned on commercial documents:

• N – No modification
• H – Heating
• O – Oil/Resin
• W – Waxing
• I – Impregnation
• R – Irradiation
• U – Diffusion
• B – Bleaching
• D – Dyeing
• F – Filling
• C – Coating
• HPHT – High Pressure High Temperature

Lapislazuli (“blue stone”) is famous for its blue color. It is a rare opaque aggregate (combination of minerals) composed of Lazurite and interspersed with Pyrite and other minerals. Traces of Pyrite are often seen as a sign of authenticity. In ancient times ground Lapislazuli was the main ingredient in ultramine pigment. Main origins are the Hindukush Mountains in Afganistan, and some sources in Chile and Russia. (Ostendorff; Schumann)

Before technology allowed more sophisticated ways of mineral identification, mineralogist Friedrich Mohs (1773-1839) developed a system of identification based on the relative hardness of substances. He chose 10 typical substances of consequtively increasing hardness and ranked them from 1 to 10 depending on what scratches what. (Schumann)

The Mohs scale is a popular yet stricly relative measure. The scales by Rosiwal who measured the intensity of grinding using a water-based abrasive, and Knoop who measured the depth of an indent made by a diamond-pointed tool applied with a fixed amount of pressure, are considered absolute scales of hardness. While they concur with Mohs’ relative ranking they show big absolute differences in hardness among the substances, in particular the extreme hardness of diamond, a point the Mohs scale does not reveal in any adequate degree.

Rubellite is the reddish pink variety of Tourmaline, occasionally with a violet hue. The most valuable color is “Ruby-Red”. Historic origins are the Ural Mountains, Elba and California. (Ostendorff)

Pictured: CADEAUX JEWELRY’S Paladin series features a truly irreplaceable ring with a 42 carat Rubellite engraved by German gemstone artist Erwin Pauli with an image of Cleopatra, queen of Egypt (69 BCE to 30 BCE).

Rutile is a mineral (Titanium Dioxyde), which crystallizes in long needle-like structures of red (“rutilus” meaning red or golden reddish in Latin), golden or metallic color. Rutile is often embedded in metamorphous rocks, meaning in rocks that have changed shape typically through the process of crystallization, such as Quartz. Main origins are Norway, Brazil, USA. (Ostendorff)

Pictured: CADEAUX JEWELRY’S Paladin extraordinary SPHYNX ring in 18 Kt gold with a Tourmaline cat’s head and a Rutilated Quartz torso, also set with yellow Sapphires, Rubies, Diamonds.

Tanzanite is a commercial name for blue Zoisite (Calcium Aluminium Silicate) first used by an American jewelry retailer. This variety of mineral was discovered in Tanzania, Africa in the 1960s, hence the name. In lustre, color and clarity it can often compete with Sapphire, however, it does not have the same characteristics, especially in terms of harndess. The most sought after color is a deep ultramarine blue, but often this gems has a slight violet tinge. (Schumann)

Pictured: A beautiful natural Tanzanite crystal of 61 cts acquired by CADEAUX JEWELRY in 2011. This crystal is being mounted in a piece of jewelry as is, uncut and unpolished.

Tourmaline is a complicated mixed crystalloid configuration that yields the biggest variety of colors among all gemstones. Green is the best known color, culminating in a much sought after saturated green referred to as Chrome Tourmaline, but Tourmaline occurs also in a variety of reds, pinks and violets (Rubellite), and in blue and white hues. Historic origin of Tourmaline is Ceylon (“tourmali” being a Ceylonese term of unknown meaning), Brazil, and Africa. (Ostendorff; Schumann)

Pictured: CADEAUX JEWELRY’S Paladin extraordinary SPHYNX ring in 18 Kt gold with a green Tourmaline cat’s head and a Rutilated Quartz torso, also set with yellow Sapphires, green Tsavorites, Rubies, Diamonds.

Turquoise is a Copper-Aluminum-Phosphate in the Apatite family that often occurs in form of boulders that have an opaque oily luster and a greenish-blue hue. Because Turquoise also contains water, it is susceptible to exposure to heat and to contact with cosmetics or other chemicals, which may all cause discoloration. Thus Turquoise jewelry should be spared contact with cosmetics and removed while washing with soap. The name Turquoise derives from the old trade routes that brought the stone to the Occident via Turkey. Main origins are Persia (Iran), Afganistan, China, Tansania and Florida (USA). (Ostendorff; Schumann)

Pictured: CADEAUX JEWELRY Cult series Il Magnifico rings in 18Kt gold, skulls carved from Turquoise (right), Chalcedony and Black Jade.