Virtue One

Shine

As in all things, true beauty comes from within — so the virtue rated above all others in a South Sea pearl is its lustre. Lustre is the result of light reflected from the pearl's surface combined with its deep inner glow, or iridescence. South Sea pearls are built from many fine layers of a crystal-like substance called nacre, secreted from within the living tissue of the oyster. The quality and thickness of that nacre gives a pearl both its radiance and its depth of glow.

The combination of light reflecting on the pearl's surface, and light refracting between each layer of nacre within it, is what makes this gem unique. Lustre has the magic to minimise other imperfections, and is considered the very soul of the pearl.

Five Broad Categories of Lustre

Virtue Two

Surface

There are two essentials to assessing the surface of a pearl: its blemishes, and its grain. The surface of a pearl is, essentially, its skin. Because South Sea pearls carry layers of lustrous nacre built up over time, a flawless surface is extremely rare. As a gift of nature from a living mollusc, even the most beautiful and valuable pearls may carry slight imperfections — naturally bestowed beauty marks that characterise each pearl as an individual creation.

Blemishes

Blemishes come in many varieties. The most common are the spot — a small, shallow hole or indented scar; the bump — a raised, sometimes discoloured scar; the chip — an area that appears cut or chipped away; the scratch — a fine line; and the wrinkle — small creases producing a crumpled appearance.

Autore has developed a grading system to identify the extent of visible blemishes, regardless of type. A single pearl may sit between two grades; a strand may be made up of pearls of differing grades.

Baroque pearls are graded differently — predominantly on shape, surface appearance and their versatility in jewellery, rather than by blemish alone. Grade A denotes smooth skin with good lustre; Grade B, smooth skin spotted or wrinkled on less than 30% of the surface; Grade C, extreme asymmetry with similar surface marking; and Grade D, heavy spotting, wrinkling or discolouration beneath the surface.

Pearl Grain

Pearl grain refers to the composition of the pearl's skin and its underlying structure. The tighter that structure, the less evident the grain, which appears as slight ripples across the surface. Where the grain is only just visible, it lends the pearl a subtly fractured appearance; as these fractures grow larger and more evident, they read as fine cracks within the pearl's structure.

A pearl's full surface grade combines both readings — for example, a perfectly clean pearl with a very slight grain is classed A/VSL; the same pearl with grain clearly visible as cracking becomes A/MD or A/HY.

Virtue Three

Shade

The species of oyster, and the environment in which it grows, are the principal factors behind a pearl's colour and complexion. South Sea pearls are prized for their rich and varied hues. Pearls from the Pinctada maxima oyster arrive in shades of white, ivory, silver, blue, yellow and rich gold. Pearls from the Pinctada margaritifera — known as Tahitian, or black, pearls — arrive in aubergine, blue, green and grey, each with its own undertone. Every pearl reflects colour differently: boldly across the surface, or hinting at hues from deep within its layers of nacre.

White Range

Yellow & Gold Range

Black & Tahitian Range

Pearls from the Pinctada margaritifera oyster carry a spectrum entirely their own — from deep aubergine through peacock green to royal blue and grey, each shot through with secondary overtones.

Illustrative swatches only. Photographic reference for Tahitian colour grading belongs to the Pacific Pearl Colors Poema chart and is not reproduced here.

Colour Depth & Hue

Every base colour comes in dark and light forms. A South Sea pearl may be labelled intense when its colour runs extremely deep, or light when it carries only the softest hint of colour — coded as I and L respectively. Variations occur often, and two colours can combine: a pearl might be described as I SIL/BLU (Intense Silver Blue) or L YEL/GRN (Light Yellow Green).

South Sea pearls also carry beautiful iridescent overtones, most often in pinks and greens, born of the same layered nacre that gives them their lustre. Where more than one hue appears, the dominant hue is named first, followed by the secondary hue marked SL for slight — for example, WH/PK SL GRN describes a White Pink pearl with a slight Green overtone.

Pink overtones are among the most sought-after in the South Sea palette, appearing as a soft blush across white, green or gold base colours.

Green overtones lend a cool, opalescent quality, often catching the eye as the pearl turns in the light.

Blue overtones range from a cool steel to a warm, dusky rose-blue, and are prized for their rarity.

Colour is a highly subjective quality, and current market demand may favour some colours over others — though colour alone never solely determines a pearl's allure. Shine, Surface, Shade, Shape and Size combine to make each South Sea pearl unique. Colours shown here are indicative; for an exact reference, consult an industry-approved pearl pantone guide.

South Sea pearls arrive in a remarkable variety of shapes, making them a uniquely difficult gem to classify without a trained eye. The major categories are Round, Near Round, Drop, Button, Baroque and Circle — and with the exception of Round and Near Round, each category holds its own family of variations.

Round & Near Round

Pearls are formed in oysters seeded with a spherical bead, or nucleus, of freshwater mussel shell — yet only a small percentage of harvested pearls emerge perfectly round. As a broad principle, a pearl is considered Round when the variation across its diameter is less than 2.5%: a 10mm pearl may vary by up to 0.25mm, a 20mm pearl by up to 0.50mm.

A pearl is classed Near Round when that variation runs roughly beyond 2.5%. Near Round pearls are prized for jewellery and strand-making, as they read as round once set.

Drop

The Drop family spans Teardrop, Oval and Egg shapes, alongside the more unusual Semi Drop and Cone. The one constant: a Drop pearl's vertical axis must always run longer than its horizontal axis. The greater that difference, the rarer and more unusual the pearl.

Button

In direct contrast to the Drop, a Button pearl's vertical axis must always run shorter than its horizontal axis. A High Button can appear close to Near Round once set.

Baroque

The most individual of all South Sea pearls, the Baroque is irregular or free-form in shape. Where relatively symmetrical, it can be set in strikingly varied jewellery designs. Occasionally a Baroque pearl carries what is known as a "fish tail"; where one side is symmetrical or round, it is classed Semi Baroque.

Circle

A pearl bearing one or more parallel grooves around its circumference is classed a Circle — any shape may qualify, with one exception: a Drop pearl ringed at its apex is classed Semi Drop, not Circle.

Non-Beaded — Keshi

Possessing an allure entirely its own, a non-beaded South Sea pearl — a "Keshi" — is created by chance, when the oyster rejects its nucleus but retains the mantle tissue originally inserted to form the pearl sac. The oyster continues to secrete nacre, forming the Keshi pearl from pure nacre alone.

South Sea pearls are renowned for their scale — the Pinctada maxima is the largest oyster species capable of producing a pearl. They are measured in millimetres, most commonly ranging from 9–20mm and beyond, with the majority falling between 10 and 17mm. The irregularly shaped Baroque pearl, though rare, can reach 40mm or more; the largest fine-quality Round South Sea pearl cultivated by an Autore producer, Cygnet Bay Pearls, measured a magnificent 22.8mm.

Pearls are generally measured with a milligauge, accurate to within 0.01mm — with the exception of Baroque pearls, whose irregularity makes milligauge measurement impossible; these are instead measured by sieve.

The pearl's weighing unit is the momme, a traditional Japanese measure still used industry-wide: one momme equals 3.75 grams, or 18.75 carats.

All five virtues — Shine, Surface, Shade, Shape and Size — combine to determine the value of a South Sea pearl. As a general guide: