Emerald is the name given to the most precious stone in the beryl group. The English word "emerald" is derived from the Greek word "smaragdos," which means "green stone." Most emeralds are permeated by hairline fissures and inclusions. Perfect gemstones with a rich, dark green color are rarities and are more valuable than comparably sized diamonds. The most beautiful specimens come from Colombia and typically have colorless inclusions. The beautiful green color is cloudier in emeralds from nearly all other sources elsewhere in the world. This cloudiness, however, is no longer regarded as a shortcoming and is known as "jardin. Emeralds are frequently cut and polished in the so-called terrace cut or emerald cut.

Emerald cut is the term used to describe an octagonal terraced cut that's most commonly used on emeralds because this cut best complements the character of the gemstone. The emerald has only moderately high refraction and is comparatively delicate. Furthermore, most emeralds occur in elongated crystalline shapes: the elongated shape of the emerald cut conforms with the natural shape of the gem and thus minimizes the volume of stone which is lost during cutting and polishing. At first glance, the emerald cut appears rectangular. Its octagonal shape is created by beveling the corners. Beveled corners protect the stone against damage during the setting process.

Enamel is pulverized glass that has been melted at a high temperature so that it fuses onto a metal substrate. The raw material for enamel is a colorless vitreous mixture which acquires its various hues from the presence of metal oxides. Enamel powder can be sprinkled dry through a sieve or painted wet onto a substrate applied as a viscous paste consisting of powder, water, and plant-based glue. There are four different kinds of enamel: opaque enamel; transparent enamel; translucent, shimmering "opal" enamel; and painter's enamel, in which fine opaque colored powder is painted onto and then kiln-fused onto an enamel background.

The verb "to engrave" is derived from the French word "graver" and describes the act of cutting script or ornamental patterns into metal, glass, or stone surfaces. The beginnings of this extremely old technique can be traced as far back as the Bronze Age. An engraving can be either raised or inset. Nowadays engraving can be executed either manually (by an engraver using a burin or an engraving needle) or by machine. Gemstones can also be engraved, in which case they are known as "intaglios" or "cameos." Wempe Jewelers can individualize a piece of jewelry by engraving it with the initials of its owner.

An expertise is a written appraisal drafted by a specialist and stating the value of a piece of jewelry or certifying the quality of a precious stone. The document summarizes the essential items of information about the piece: for example, it specifies the weight (in carats) or the purity (clarity) of a diamond. Upon request and for a fee, Wempe Jewelers will draw up an expertise for its pieces of jewelry. Diamond jewelry from Wempe Jewelers (solitaires starting at 0.25 carats; pavé starting at 0.50 carat) is accompanied by a certificate at the time of its sale. This certificate summarizes the most important items of information about the piece.