Ring – Aquamarine & Diamond Three-Stone
A modern ring principally featuring a precision cut¹ aquamarine with two round brilliant-cut diamonds in a claw setting, entirely constructed from platinum. Circa 2018.
Assessment of the Aquamarine.
Cut: oval barion-cut² (eight main brilliant-cut crown over a modified brilliant-cut pavilion, designed by Robert Long and Norman Steele³, circa 1986).
Measuring: 8.16mm x 6.62mm 5.34mm.
Weight (weighed prior to setting): 1.51cts.
Colour: pale blue (10B.4/7).
Assessment of the Diamonds (average stated where applicable).
Cut: round brilliant-cuts.
Measuring approximately: 4.00mm.
Total weight (stones weighed prior to setting): 0.51cts.
Details of the Setting.
Hallmarked: 950 platinum, Birmingham convention mark.
Sponsor’s mark: ‘GL’.
Finger size: N.
¹. Gemstones are fashioned by way of cutting facets (flat surfaces). In the majority of cases the accuracy and precision of faceting, along with the quality of surface polish are regarded as less important – instead being cut to retain as much weight as possible. This result never makes the most of the unique optical properties a gemstone. Much light entering the gemstone is instantly lost out of the back (‘windowing’), or completely absorbed (extinction).
‘Precision cuts’ (sometimes called designer cuts) describe stones produced by cutters who employ highly specialised equipment which allows for assured repeatability, precision, and accuracy. The process of obtaining a highly flat facet requires the cutter to return to each facet time and time again, with ever finer cutting laps – consequentially each facet may be cut, and then re-cut between four and ten times. A finely cut facet improves the quantity and sharpness of light. The quality of light is further enhanced by close attention to the particular optical properties inherent to the nature of the material being cut – these facets are optimally angled for reflection. Such techniques allow cutters to produce designs which are unavailable from traditional techniques; superlative gems, some with unusual facet designs, or unique face up patterns.
². A barion cut is not a shape, but rather a new conceptual method for cutting a gemstone, which enhances the appearance beyond traditional cuts. “The barion was developed in October 1970 by Basil Watermeyer, a diamond cutter in Johannesburg, Republic of South Africa. The predominant feature of the barion style of cutting is the half-moon facets at the girdle. In the original square barion these were single, steep angled facets along each side of the stone. In adapting the barion concept to outlines other than angular shapes (straight sides), these single half-moon facets have evolved into a group of facets which taken together accomplish the same function as did the original single half-moon facet, i.e. to link and essentially round a brilliant pavilion centre to a non-round outline” (Robert Long and Norman Steele, ‘Facet Design Volume 6. Barions’, 1987). A round brilliant pavilion is one of the most effect facet designs for light reflection due to the high number of planes of symmetry, and so being able to combine this with non-round outlines enhances the appearance and liveliness of a facet design. Indeed, the effect can be so striking that the level of scintillation is similar to that normally observed only for round diamonds. Since the inventor was a diamond cutter it therefore shouldn't be surprising that this outcome should be so similar. As Mr Watermeyer explains, in referring to an emerald cut diamond and a barion emerald cut diamond – “the barion has brought a most spectacular change to the well-known and popular emerald-cut. Though it is basically a mixed cut, the barion emerald-cut is accepted as a brilliant cut, and supersedes the standard emerald-cut” (Basil Watermeyer, ‘Diamond Cutting. A Complete Guide to Diamond Processing’,1984).
³. Robert Long was an engineer with Boeing in the 1950s, and worked on the Saturn 5 space mission in the 1960s. This background in precision lead him to the development of a pioneering faceting technique in the 1970s – ‘meet point’ faceting. Placing a sequence of facets on a gemstone is not a straightforward task. However, with the assistance of Norman Steel, a fellow Boeing computer programmer and interested mineral scientist, they applied three-dimensional geometry to exactly this problem. The outcome was special technique that allowed a cutter to approach a facet design and follow a disciplined set of instruction to exactly reduce a design, correct to a hundredth of a degree and without having to rely on direct measurement. The ‘meet point’ in the name is in reference to the apex, or junction, of three or more simultaneous intersections of facets; an essential element to the technique. This attention to details directly inspired faceting machine manufacturers to refine their products and improve the quality of materials and accuracy. Long and Steele produced a series of revolutionary books in faceting and are jointly regarded as leading proponents of precision cutting.