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A doublet is a type of assembled gem composed in two sections. [1] It is sometimes used to imitate other, more expensive gems. Opal Doublet. A garnet and glass doublet uses a top portion of natural garnet fused to any color of glass to imitate a gem. The color of glass used in the doublet is all that is seen, as the garnet provides no color.
Classically the designs carved onto cameo stones were either scenes of Greek or Roman mythology or portraits of rulers or important dignitaries. In history, agate portrait cameos were often gifts from royalty to their subjects. These antique cameos, some more than 2000 years old, are either displayed in museums or are in private collections.
A 17th century English lapidary text. The etymological root of the word lapidary is the Latin word lapis, meaning "stone". [5] In the 14th century, the term evolved from lapidarius, meaning 'stonecutter' or 'working with stone', into the Old French word lapidaire, meaning 'one skilled in working with precious stones'.
Stone has been used for carving since ancient times for many reasons. Most types of stone are easier to find than metal ores, which have to be mined and smelted. Stone can be dug from the surface and carved with hand tools. Stone is more durable than wood, and carvings in stone last much longer than wooden artifacts.
Because strontium titanate and glass are too soft to survive use as a ring stone, they have been used in the construction of composite or doublet diamond simulants. The two materials are used for the bottom portion (pavilion) of the stone, and in the case of strontium titanate, a much harder material—usually colorless synthetic spinel or ...
A ruff from the early 17th century: detail from The Regentesses of St Elizabeth Hospital, Haarlem, by Verspronck A ruff from the 1620s. A ruff is an item of clothing worn in Western, Central and Northern Europe, as well as Spanish America, from the mid-16th century to the mid-17th century.
The hardest stone frequently carved is granite, at about 8 on the Mohs scale. It is the most durable of sculptural stones and, correspondingly, an extremely difficult stone to work. [2] Basalt columns, being even harder than the granite, are less frequently carved. This stone takes on a beautiful black appearance when polished.
In Slocum stone, the play of color takes the form of tinsel-like patches. The visible structure is also considerably different; in the imitations, the body of the stone is transparent to translucent from certain angles, whereas ammolite is entirely opaque. Gemologically speaking, ammolite can be grouped with the shell-based marbles.