Emerald is the name given to the most precious stone of the beryl group. The English word "emerald" comes from the Greek word "smaragdos", which means "green stone". Most emeralds are permeated with cracks and inclusions of the hairline. Perfect gemstones with a rich dark green color are rarities and are more valuable than diamonds of comparable size. The most beautiful specimens come from Colombia and generally have colorless inclusions. The beautiful green color is cloudier in emeralds from almost all other sources in other parts of the world. This cloudiness, however, is no longer considered a gap and is known as "jardin". Emeralds are often cut and polished in the so-called terrazzo cut or emerald cut.

Emerald cut is the term used to describe an octagonal row cut that is most commonly used on emeralds because this cut better complements the character of the gemstone. Emerald has only moderately high refraction and is relatively delicate. In addition, most emeralds occur in elongated crystalline forms: the elongated shape of the emerald cut conforms to the natural shape of the gem and thus minimizes the volume of stone that is lost during cutting and polishing. At first glance, the emerald cut appears rectangular. Its octagonal shape is created by dismolding the corners. The unveiled corners protect the stone from damage during the setting process.

Enamel is pulverized glass that has been melted at high temperature so that it melts onto a metal substrate. The raw material for enamel is a colorless vitreous mixture that acquires its various shades from the presence of metal oxides. Enamel powder can be dry sprinkled through a sieve or painted wet on a substrate applied as a viscous paste composed of powder, water and vegetable glue. There are four different types of enamel: matte enamel; transparent enamel; translucent, shimmering "opal" enamel; and the painter's enamel, in which fine powder of opaque color is painted on and then oven-melted on an enamelled background.

The verb "engrave" comes from the French word "graver" and describes the act of cutting scripts or ornamental motifs into metal, glass or stone surfaces. The beginnings of this extremely ancient technique can be traced back to the Bronze Age. An incision can be raised or probed;nowadays engraving can be done manually (by an engraver using a burin or engraving needle) or by machine. Precious stones can also be engraved, in which case they are known as "intaglios" or "cameos". You can individualize a jewel by engraving it with the initials of its owner.