The AUTORE FIVE S's
AUTORE’s critically acclaimed pearl classification guide, the AUTORE Five S’s™ was launched in 2007 and continues to play an important role as an educational tool to build confidence for consumers and retailers to buy, sell and wear South Sea pearls.
Rosario Autore developed the South Sea Cultured Pearl Classification Guide which has been recognised by the respected Gubelin Gem Laboratories. The guide considers the quality of a South Sea Pearl based on its Shine, Surface, Shade, Shape and Size, and provides an in-depth explanation to understand pearl classification.
AUTORE’s founder and CEO, Rosario Autore, was awarded a medal of distinction by the French Senate in September 2008, in recognition of his valuable work and dynamism in creating a trade standard for the classification of pearls, the AUTORE Five S’s South Sea Pearl Classification Guide™.
The AUTORE Five S’s is a registered trademark of Autore Pearls Pty. Ltd.
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 (iridescence). South Sea pearls are made up of many fine layers of a crystal-like substance called nacre, comprising of organic and inorganic materials secreted from within the living tissue of the oyster. The quality and thickness of nacre gives a pearl both its radiance and its deep glow. The combination of light reflecting on the pearl’s surface and light refracting between each layer of nacre within the pearl is what makes this gem unique. Lustre has the magic to minimise other imperfections and is considered the soul of the pearl.
I
Brilliant lustre
Producing a mirror reflection
II
Excellent lustre
Producing a very clear reflection
III
Good lustre
Producing a good reflection
IV
Average lustre
The reflection appears opaque
V
Poor lustre
Producing very little reflection
Surface
There are two essentials aspects to be considered when assessing the surface of a pearl,
blemishes and the pearl’s grain
BLEMISHES
The surface of a pearl is essentially its skin. Because South Sea pearls have layers of lustrous nacre built up over time, a flawless surface is extremely rare. As pearls are a gift of nature from a living mollusc, the most beautiful and valuable pearls may still have slight imperfections which appear in the form of small blemishes. These naturally bestowed ‘beauty marks’ characterise each pearl as an individual creation. Blemishes come in many varieties. The most common blemishes are listed below.
A grading system has been developed by AUTORE to identify the extent of visible blemishes, regardless of type. Sometimes an individual pearl or strand can be classified with more than one of these grades. A single pearl, in this case, would mean it is in between grades and a strand would be made of pearls with different grades.
Blemish Categories
Spot
The most common type of blemish, which usually appears as a small, shallow hole, a sunken area or a small indented scar on the pearl’s surface
Bump
A blemish resembling a raised scar or blister. Bumps are uneven and sometimes discoloured areas of the pearl’s surface
Chip
An area of the pearl’s surface which appears to be cut out or chipped off
Scratch
A mark resembling a line produced by scratching
Wrinkle
Small creases on the pearl’s outer layer producing a crumpled or shrunken appearance
Grades
A
Blemish free or very small blemishes hardly discernable by the naked eye
B1
One to four visible blemishes concentrated on one small area of the pearl
B2
Blemishes visible on 30% of the pearl’s surface, not necessarily on the same area
C1
Blemishes visible on 50% or more of the pearl’s surface, not necessarily in the same area
C2
Heavy blemishes on the majority of the pearl’s surface
D
Heavy or deep blemishes and/or thin coating of nacre
BAROQUE
The grading of a Baroque pearl differs from all other South Sea pearl shapes. Its grade is based predominantly on its shape, surface appearance and its ability to be diversely used in jewellery and strands, rather than by reference to its surface blemishes and pearl grain.
A
Smooth skin with good lustre however not necessarily spotless
B
Smooth skin with good lustre, spotted or wrinkled on less than 30% of the pearl’s surface
C
Extremely asymmetrical, spotted or wrinkled on less than 30% of the pearl’s surface
D
A ‘D’ grade baroque pearl could be classified on the following characteristics:
Heavy spotting on the majority of the pearl’s surface, Heavy wrinkling on the majority of the pearl’s surface or Discolouration under the pearl’s surface
PEARL GRAIN
The pearl grain refers to the composition of the pearl’s skin and its structure. The tighter the structure of the pearl, the less evident is its grain. The grain will appear as slight ripples on the pearl’s surface. In cases where the grain is only just visible, it will give the pearl a slightly fractured appearance. As these fractures become larger and more evident, they will appear as ‘cracks’ within the structure of the pearl.
For example, a perfectly clean pearl with a very slight grain will be considered an A/VSL. In the case where a pearl is still perfectly clean but where the grain is clearly visible, appearing as ‘cracks’, the pearl will be classified as a A/MD or A/HY.
CL
(CLEAR)
No pearl grain visible
VSL
(VERY SLIGHT)
Very slight pearl grain visible
SL
(SLIGHT)
Slight pearl grain visible on 30% of the pearl’s surface
MD
(MEDIUM)
Medium pearl grain visible on 50% or more of the pearl’s surface
HY
(HEAVY)
Heavy pearl grain visible on entire pearl surface
Shade
The species of oyster and the environment in which they grow are the main factors behind
determining a pearl’s colour and complexion. South Sea pearls are highly coveted for their rich,
varied colours. Pearls from the Pinctada maxima oyster come in shades of White, Ivory, Silver, Blue,
Yellow and rich Gold. Pearls from the Pinctada margaritifera oyster (referred to as Tahitian or Black
pearls) come in shades of Aubergine, Blue, Green and Grey, all with various hues. Every pearl reflects
colour in a different way – boldly on the surface or hinting at hues from within layers of nacre.
South Sea pearl colours can be categorised as belonging to either a White, Yellow or Black range.
COLOUR DEPTH AND VARIATIONS
COLOUR CODE
I= Intense
L= Light
White Range
Gold Range
Black Range
HUE
South Sea pearls often show beautiful iridescent overtones, especially pinks and greens. These hues come from the layered structure of nacre and the behaviour of light as it reflects from both the upper and lower layers of the pearl’s surface. In some cases, more than one hue is visible. To categorise this, the dominant hue will be listed first followed by the more subtle hue, this is classified as ‘slight’ (SL). For example WH/PK SL GRN (WhitePink Slight Green).
Colour is a highly subjective quality and current market demands may result in higher prices for some colours more than for others. However, it is important to remember that although colour adds to the beauty of a pearl, it does not solely determine its allure. Shine, Surface, Shade, Shape and Size combine to make each South Sea pearl unique.
PINK HUES
White Pink
Green Pink
Gold Pink
GREEN HUES
White Green
Silver Green
Gold Green
BLUE HUES
Silver Blue
Pink Blue
Green Blue
Shape
South Sea pearls come in a variety of shapes, making them an incredibly difficult gem to classify
without a professionally trained eye. A product of nature, each pearl is individual and unique.
The major categories of South Sea pearl shapes are; Round, Near Round, Drop, Button, Baroque
and Circle. With the exception of Round and Near Round pearls, there is a variation of different
types within each shape category. However, to simplify pearl shapes, some general principles
can be applied.
Round
Pearls are formed in oysters seeded with a spherical bead (nucleus) made from freshwater mussel shell. Only a small percentage of harvested pearls are perfectly round. As a broad principle, a pearl is considered Round when the variation in its diameter is less than 2.5%. Therefore, a pearl measuring 10mm can have up to 0.25mm variance and a pearl measuring 20mm can have up to 0.50mm variance.
Near Round
A pearl is classified Near Round rather than Round when the variation in its diameter is roughly more than 2.5 %. This percentage may vary when there are lumps or slight variations to the pearl’s shape. Near Round pearls are ideal for jewellery and strand making as they appear round once set.
Drop
There are several types of pearls that fall within the Drop shape category. They include Teardrop, Oval and Egg shaped pearls, as well as the more unusual Semi Drop and Cone shapes. While variations in the category can be quite dramatic, the one basic principle is that the vertical axis of a Drop pearl must always be longer than its horizontal axis. Short Oval shaped pearls can be similar to Near Round pearls in appearance. The greater the difference in size between the vertical axis and the horizontal axis, the more unusual and rare the pearl is.
Button
As with the Drop category, Buttons can also vary dramatically in appearance. However, in direct contrast to a Drop pearl, the vertical axis of a Button pearl must always be shorter than its horizontal axis. High Button pearls can be similar to Near Round pearls in appearance.
Baroque
The Baroque pearl is the most individual South Sea pearl produced by the Pinctada maxima oyster. Generally speaking, a Baroque pearl is irregular or free form in shape. If the Baroque pearl is relatively symmetrical, it can be used in a number of different ways in jewellery and strands. Occasionally, Baroque pearls will have what are called ‘Fish Tails’. In some circumstances, one side of a Baroque pearl will be symmetrical or round, these pearls are classified as Semi Baroque.
Circle
A pearl that has one or more parallel grooves etched around its circumference is called a Circle. All shapes can be classified as Circle pearls if these rings or grooves are present. The only exception is when a Drop pearl has a ring around its apex, in which case the pearl is classified as a Semi Drop and not a Circle.
Keshi
Possessing an individual allure entirely different to that of a nucleated cultured pearl, a non-beaded South Sea pearl (‘Keshi’) is created by chance when the oyster rejects the nucleus but retains the mantle tissue, that was originally inserted for the creation of the pearl sac. This enables the oyster to continue to secrete nacre which forms the ‘Keshi’ pearl.
Round
Pearls are formed in oysters seeded with a spherical bead (nucleus) made from freshwater mussel shell. Only a small percentage of harvested pearls are perfectly round. As a broad principle, a pearl is considered Round when the variation in its diameter is less than 2.5%. Therefore, a pearl measuring 10mm can have up to 0.25mm variance and a pearl measuring 20mm can have up to 0.50mm variance.
Near Round
A pearl is classified Near Round rather than Round when the variation in its diameter is roughly more than 2.5 %. This percentage may vary when there are lumps or slight variations to the pearl’s shape. Near Round pearls are ideal for jewellery and strand making as they appear round once set.
Drop
There are several types of pearls that fall within the Drop shape category. They include Teardrop, Oval and Egg shaped pearls, as well as the more unusual Semi Drop and Cone shapes. While variations in the category can be quite dramatic, the one basic principle is that the vertical axis of a Drop pearl must always be longer than its horizontal axis. Short Oval shaped pearls can be similar to Near Round pearls in appearance. The greater the difference in size between the vertical axis and the horizontal axis, the more unusual and rare the pearl is.
Button
As with the Drop category, Buttons can also vary dramatically in appearance. However, in direct contrast to a Drop pearl, the vertical axis of a Button pearl must always be shorter than its horizontal axis. High Button pearls can be similar to Near Round pearls in appearance.
Baroque
The Baroque pearl is the most individual South Sea pearl produced by the Pinctada maxima oyster. Generally speaking, a Baroque pearl is irregular or free form in shape. If the Baroque pearl is relatively symmetrical, it can be used in a number of different ways in jewellery and strands. Occasionally, Baroque pearls will have what are called ‘Fish Tails’. In some circumstances, one side of a Baroque pearl will be symmetrical or round, these pearls are classified as Semi Baroque.
Circle
A pearl that has one or more parallel grooves etched around its circumference is called a Circle. All shapes can be classified as Circle pearls if these rings or grooves are present. The only exception is when a Drop pearl has a ring around its apex, in which case the pearl is classified as a Semi Drop and not a Circle.
Keshi
Possessing an individual allure entirely different to that of a nucleated cultured pearl, a non-beaded South Sea pearl (‘Keshi’) is created by chance when the oyster rejects the nucleus but retains the mantle tissue, that was originally inserted for the creation of the pearl sac. This enables the oyster to continue to secrete nacre which forms the ‘Keshi’ pearl.
Size
South Sea pearls are renowned for their large sizes. The Pinctada maxima oyster is the largest species of oyster capable of producing a pearl.
South Sea pearls are measured in millimetres. South Sea pearls commonly range from 9-20+mm, with the majority falling within a range of 10-17mm. Though extremely rare, the irregularly shaped Baroque South Sea pearl can reach sizes up to 40mm or more. The largest fine quality Round South Sea pearl cultivated by one of AUTORE’s South Sea pearl producers, Cygnet Bay Pearls, measured in at a magnificent 22.8mm.
Pearls are generally measured using a milligauge which can measure the pearl to within 0.01mm
accuracy. The exception is in relation to the size of Baroque pearls which are usually impossible to measure by milligauge because of their irregularity. Consequently, Baroque pearls are measured by sieve.
The lines indicate the points at which the diameter of each pearl is measured.
