How to draw faceted stones
Brilliant cut style
In this style, the inclined facets are triangular or more or less kite shaped. The inclined facets are shown shaded in Figure D.
The most important of the brilliant cut styles is the STANDARD ROUND 58 FACET BRILLIANT Chart-2. The crown consists of 33 facets: one table, eight star facets, eight bezel facets, and 16 upper-girdle facets (also known as top-half or top-break facets). The pavilion consists of 25 facets: one culet, eight pavilion facets, and 16 lower-girdle facets (also called bottom-half or lower-break facets). The culet is sometimes omitted, in which case the pavilion consists of 24 facets.
Figures E and F outline a simple step-by-step method of drawing the crown and pavilion of the round brilliant. The crown is formed by combining diagrams A through F in Figure E as follows:
(A) Draw a circle,
(B) place a square in the circle,
(C) place a, second square at a 45°angle to the first square,
(D) draw lines from the points of the square to the circle,
(E) draw a light dotted tine through the center of the circle and through the point formed by the two adjoining star facets,
(F) connect the points of the star facets with the midpoints found in Step E.
(A) Draw a circle,
(B) place a cross in the circle,
(C) place another cross at a 45°angle to the first cross,
(D) draw a smaller circle inside the first circle,
(E) draw lines from the intersection of the small circle and the cross lines to the midpoints of the are on the larger circle (these form the pavilion facets),
(F) draw the seven other pavilion facets (as in the preceding step), erase the small center circle, and draw a tiny circle to indicate the culet.
Other modifications of the brilliant cut style, which are illustrated on the accompanying plates entitled "Cutting Styles", include the following: old European cut, Brazilian cut, English square-cut brilliant, old-mine cut, Libson cut, double-cut brilliant, semi-navette, scissors cut, spiral cut, Portuguese cut, brilliant-cut briolette, zircon cut, honeycomb cut, Cairo star cut, star cut, marquise cut, pear-shape cut, heart-shape cut, single cut, French cut, all rose cuts, rondelle, Swiss cut, split brilliant cut, twentieth century cut, King Cut, oval cut, English round-cut brilliant, jubilee cut, Magna Cut, half-moon cut. (Note: The King Cut and Magna Cut are patented styles used only for diamonds).
This style is distinguished by the fact that one or more of the edges of ALL of the inclined facets are parallel to the girdle edge (Figure G). The facets are usually arranged in rows or tiers that resemble a flight of stairs; hence the name.
The most important of the step-cut styles is the EMERALD CUT. It is usually rectangular but is sometimes square, in which case it is known as a SQUARE EMERALD CUT. It has rows of elongated rectangular facets on the crown and pavilion, parallel to the girdle, and with corner facets. Corresponding facets are usually placed on the girdle.
The number of rows, or steps, may vary 58 facets (including the eight facets on the girdle) is the usual number on an emerald-cut stone.
The emerald cut and other modifications of the step-cut style, which are illustrated on the accompanying plates entitled "Cutting Styles" include the following; trap brilliant, square emerald cut, baguette, tapered baguette, square cut, table cut, bevel cut, step-cut bead, triangle cut, bullet cut, keystone cut, hexagon cut, long hexagon cut, kite cut, lozenge cut, trapeze cut, pentagon cut, epaulette cut, tapered pentagon cut, cut-corner triangle, octagon cut, whistle cut, rhomboid cut, fan-shape cut, shield cut, window cut.
Combinations of the brilliant and step-cut styles are called MIXED CUTS. By combining the outline name with the above terms, the style of the cut may be classified; for example, a heart-shaped brilliant-cut stone, a square step-cut stone, a rectangular mixed cut, etc.
In contrast to faceted stones, those cut with curved surfaces are called CABOCHONS (pronounced CAB-oh-shawn), and are classified as follows :
- Single Cabochon
- This styles has a curved top and a flat base. The curved surface may be high, medium or low.
- Double Cabochon
- This style has both upper and lower portions curved. It is usually steep above the girdle-and shallow below, but may be the reverse. Star stones, cat's-eyes and moonstones are usually cut in this manner.
- Hollow Cabochon
- The hollow cabochon consists of a simple cabochon with a concave depression in the base. Its main purpose is to lighten the color of an otherwise too dark stone.
- Lentil Cabochon
- This is a comparatively thin, flat variation of the double cabochon in which both surfaces have the same degree of curvature. It is commonly used for opals.
- Reverse Cabochon
- Seldom encountered in the trade, the reverse cabochon is a simple cabochon with a concave depression in its top surface. It is used primarily to produce unusual effects in star stones and cat's-eyes.
Curved and Engraved Stones
The design of a carved gem is produced by working the entire visible surface of the stone. The design of an engraved gem is produced by engraving into the stone but leaving part of the surface un-worked, thus merely providing a background for the design. The principal types are as follows:
A cameo is a carved gem produced by cutting away portions of the surface above the girdle so that the entire design is ABOVE the girdle edge. When fashioned from genuine gem materials, they are known as STONE CAMEOS; when cut from shell, they are known as SHELL CAMEOS; those of coral are called CORAL CAMEOS, etc. Cameos cut from synthetic gem materials, are known as SYNTHETIC-STONE CAMEOS, and those made from glass and other imitations are known simply as IMITATION CAMEOS.
- Intaglio (pronounced in TAL-yo)
This is a form in which the design is engraved into the stone, so that all of the design lies below the girdle edge. Sometimes the figure is engraved into the stone; occasionally the background is
engraved, leaving a raised figure. This type is used mainly as a seal. Like cameos, intaglios may be
made from natural, synthetic or imitation materials.
- Chevee (pronounced sheh-VAY)
The chevee is a flat-topped gemstone or other material with a large polished oval depression in the center.
- Cuvette (pronounced koo-VET)
The cuvette is a variety of chevee with a raised cameo design in the oval depression.
A scarab is a gemstone or other substance that has been carved or engraved to represent the scarabaeus, a beetle common to the countries bordering the Mediterranean sea.
- Statutes and figurines
These are usually carved from poorer quality gem materials to represent animals, people, leaves, flowers, temples, etc.
- Pierced Carving
This type of carving is made by drilling openings through the stone, usually as a means of removing unsightly flaws. After the flaws are removed, the drill holes are covered.
- Illusion Cut
This is a novelty form of cutting and engraving. It is made by cutting a transparent material (usually rock crystal) into the shape of a triangular block and placing grooves of various widths and inclinations on the edge of the block. when the grooves are viewed through the opposite flat surface, a three-dimensional effect is observed, due to reflection of the grooves from the other two surfaces, which are inclined towards the engraved edge.
- Plaque (pronounced PLACK)
There are many variations of this form. The distinguishing characteristic is two parallel surfaces, usually flat, with a relatively narrow space between. Some have a beveled edge, although this is not an essential characteristic. If the area between the two parallel surfaces is quite thick, the stone is usually called a tablet.
The bead is usually essentially spherical, with or without facets, but is distinguished by the fact that it always has a hole drilled through the center.
- Rondelle, or Rondelle
The rondelle is similar to the bead, but consists simply of a flat disk with a hole drilled through the center. It is generally used as a spacer or separator between beads.
As the name implies, the rod is a cylindrical form. It is usually used for flame-polished synthetic corundum or spinel.
- Oriental or Native Cut
This term is applied principally to stones from the orient that are characterized by a lack of symmetry and excessive weight saving. Stones cut in this manner usually have distorted shapes, unsymmetrical placement of facets, and other cutting faults.
- Calibre or Caliber Cut
This is a term applied to small more or less rectangular stones that are used principally to produce lines or fulfill the design of a piece of jewelry. The resulting effect is known as CALIBRE WORK, because the stones are often cut to a calibrated size in order to fit the mounting. Shapes such as the keystone are used to produce curved lines.
- Melee (pronounced MILL-ee)
Melee is a term used primarily to describe small, round faceted diamonds; however, it is also sometimes applied to colored stones of the same size and shape.
- Rose Cut, or Rosette
This is an old style of cutting that is rarely encountered except in garnets and small diamonds. The base is hut and the top is usually completely covered with small facets that meet at a point in the center of the stone. Exceptions to this general rule are such cuts as the double rose. Although rose-cut diamonds are called "diamond chips" by those who do not recognize this style of cutting, the term "chip" correctly applies only to small, irregular fragments that have a variable number of haphazardly placed, irregularly shaped facets.