PEARL QUALITY 101

jewellery designers. This is due to their remarkable range of sizes, shapes and colours, plus their commercial availability at lower price points. They are usually cultured in freshwater lakes and ponds, often with many pearls grown in one oyster. China is the leading source for freshwater cultured pearls.

Just as quality influences diamond price, the same is true for pearls.

GIA developed the Seven Pearl Value Factors for the same reasons it developed the Four Cs of diamond quality: to establish a standard terminology for describing pearl quality, using language everyone can understand. And just as the GIA defined the methods and best practices for evaluating diamond quality, it also defined the procedures for evaluating pearls. Like diamond grading, pearl classification is a complex process that takes a trained gemmologist time and extensive knowledge to execute.

There are a number of factors that influence their value and how they are assessed.

Pearl value factors

Pearls come in a wide variety of sizes, shapes and colours. The GIA Seven Pearl Value Factors is a comprehensive standard it developed over a 60-year period of ground-breaking research on pearls. It provides a systematic way to evaluate pearls of all types and to describe their appearance and quality in a way everyone can understand. The qualities that determine the overall value of a natural or cultured pearl or a piece of pearl jewellery are size, shape, colour, lustre, surface quality, nacre quality and – for jewellery with two or more pearls – matching:

1. Size The size of round and near-round pearls is expressed in terms of their diameter measured in millimetres. Other shapes are measured according to their length/depth and diameter/ width. When other value factors are equal, larger pearls are rarer and more valuable than smaller pearls of the same type.

2. Shape The three main categories of shape are spherical, symmetrical and asymmetrical (semi-baroque and baroque). Pearls come in seven basic shapes: round, near-round, button, drop, oval, semi-baroque and baroque. Round is the most difficult shape to culture, making it the rarest cultured pearl shape and – if all other factors are equal – also generally the most valuable. There are exceptions, though. Well-formed pear, oval, or baroque (irregularly shaped) cultured pearls are also prized by pearl-lovers.

3. Colour Natural and cultured pearls occur in a broad range of hues. There are warm hues like yellow, orange and pink, and cool hues like blue, green and violet. Pearls have a wide range of tone from light to dark. Pearl colours tend to be muted, with a soft, subtle quality.

Pearl colour can have three components. Body colour is the pearl’s dominant overall colour, overtone is one or more translucent

Of the seven pearl value factors, lustre might be the most important. Lustre is what gives a natural or cultured pearl its unique beauty. Different pearl varieties have different standards for lustre.

colours that lie over a pearl’s body colour and orient is a shimmer of iridescent rainbow colours on or just below a pearl’s surface. All pearls display body colour, but only some show overtone, orient or both.

The law of supply and demand determines the value of certain pearl colours at any given time. If supplies of high-quality pearls displaying a preferred colour are low, their prices can rise to unusually high levels. Other complex factors, like fashion trends and cultural traditions, can influence colour preferences.

4. Lustre Lustre is the intensity of light reflected from a pearl’s surface. Lustre is one of the factors that give a natural or cultured pearl its unique beauty. Pearls with excellent lustre have sharp, bright reflections on the surface. Different pearl varieties have different standards for lustre.

Of the seven pearl value factors, lustre might be the most important. The GIA Lustre Scale ranges from excellent to poor: • Excellent – Reflections appear bright and sharp. • Very good – Reflections appear bright and near-sharp. • Good – Reflections are bright, but not sharp and slightly hazy around the edges. • Fair – Reflections are weak and blurred. • Poor – Reflections are dim and diffused.

Within a pearl type, when other value factors are equal, the higher the lustre, the more valuable the pearl.

5. Surface Pearls commonly have blemishes or irregularities that are normally confined to the surface. Surface characteristics are judged by size, number, location, visibility and the types of blemish. If surface characteristics are numerous or severe, they can affect the durability of a pearl and severely lower its value. They have less effect on the pearl’s beauty and value if they are few in number, or if they are minor enough to be hidden by a drill-hole or mounting. The GIA Surface Scale classifies pearls as clean, lightly spotted, moderately spotted or heavily spotted.

Like coloured stones, most pearls never achieve perfection. Some might show abrasions that look like a series of scratches on the surface, a flattened section that does not affect its basic shape, or an irregular ridge that looks like a crease or wrinkle.

6. Nacre quality Nacre is the substance that makes up a pearl, layer after layer. Thickness is important when

evaluating nacre quality to ensure that cultured pearls are durable, as well as beautiful. Nacre thickness measurements are provided as optional descriptions on GIA pearl reports. However, GIA pearl reports will clearly note if the nacre coating is too thin and/or damaged, thereby posing a potential impact on a pearl’s durability.

Lustre and nacre quality are closely related. If the nucleus is visible under the nacre, or if the pearl has a dull, chalky appearance, you can assume that the nacre is thin. This affects the lustre, as well as the durability of the pearl.

7. Matching This relates to the uniformity of pearls in strands, earrings or other multiple-pearl jewellery items and is highly dependent upon a skilled grader to determine matching the other six value factors. The GIA Matching Scale ranges from excellent to poor or listed as not applicable for single pearls and certain intentionally mismatched jewellery items. Jewellery designers sometimes deliberately mix colours, shapes and sizes for unique effects, but for most pearl strands, earrings or other multiple-pearl jewellery, the pearls should match in all the quality factors.

Classifying pearls

Using standard and advanced testing equipment, GIA gemmologists specialising in pearls identify the pearl type (whether it is natural or cultured) and look for evidence of treatments. The pearl is weighed with an electronic micro-balance and its size is measured in millimetres using special digital calipers. The pearl is then compared with a set of carefully pre-selected pearl masters to determine colour and classify the other value factors. A second team of pearl specialists independently repeat all necessary observations and testing to ensure a precise and objective evaluation.

Because lighting, background colours and other environmental factors can influence observations, controlling the pearl grading environment is critical. Staff examine the pearls against a neutral grey background, using a daylight equivalent light source. Sitting about one foot away from the pearl, they rotate it to get an overall impression as they compare it with pearl masters.

This specific environment, along with the tests and the procedures conducted during the examination, were developed by the GIA to ensure repeatable, accurate and dependable results so that pearl buyers can rely on an objective pearl assessment based on the GIA’s value factors.

GIA Pearl Reports provide information on the identity of pearls (natural or cultured), the mollusc (when determinable) they originated from, the environment they formed within (saltwater or freshwater) and state whether pearls have undergone any detectable treatments. Multiple security features on GIA Pearl Reports ensure their authenticity and all reports include a digital image of the pearl(s). The GIA currently offers three types of pearl services: the GIA Pearl Identification Report Service, the GIA Pearl Identification and Classification Report Service and the GIA Cultured Pearl Classification Report Service:

Pearl Identification Report The GIA Pearl Identification Report details the quantity, weight, size, shape, colour, overtone, identity (natural or cultured), mollusc, when determinable, environment (saltwater or freshwater) and any detectable treatments.

Pearl Identification and Classification Report The GIA Pearl Identification and Classification Report includes all identification report information, as well as identification and classifications for lustre, surface and matching (if applicable).

Cultured Pearl Classification Report The GIA Cultured Pearl Classification Report is an abbreviated report that provides classification information on unmodified cultured pearls. This dossier-sized report includes a detailed classification of the submitted pearls based on the GIA’s Seven Pearl Value Factors and is specifically and exclusively for the three major types of cultured pearls: Akoya, South Sea and Tahitian pearls. No identification or advanced testing is done.

– Established in 1931, the GIA is an independent non-profit that protects the gem and jewellery buying public through research, education and laboratory services.

How winning the SLA impacted my career

HASTIE’S WIN WAS ANNOUNCED TO A host of leading figures in the diamond industry in a spectacular grand finale held in the CIRCA Gallery in Johannesburg on 13 July 2015. Hastie, from the Tshwane University of Technology (TUT) in Pretoria, picked up the highest accolade of the “Forevermark Promise Award” and received a year’s scholarship to study for a Master’s in accessory design at Poli.Design founded by Milan Polytechnic.

What triggered your desire to make jewellery?

I’ve always been creative, but I didn’t excel at school. I struggled with direction, which culminated in a matric certificate that looked more like a weather report, with highs of 40 and lows of 28. The only exception was a distinction in art.

As I didn’t get a university-entrance matric, I couldn’t enrol for the creative degrees I was interested in, which left me with limited options. I had a series of part-time jobs, including one in a gem and mineral shop. Very often jewellery students from the TUT would come in looking for stones to set in their projects and I’d assist in selecting them. Conversations would always be struck up and a seed was planted.

I woke up one day and simply decided enough was enough: I wanted to start over. I was 23 and knew I wanted to be something. I called my parLilja Hastie was the 2015 winner of the 18th De Beers Shining Light Awards, a prestigious jewellery design competition that showcases young African talent. She tells us how winning this accolade impacted her career.

ents for a sit-down and explained that I wanted to rewrite matric and open those doors. I went for aptitude tests and visited numerous open days look for options. During a visit to the jewellery design and manufacture programme at TUT, I received the results from my aptitude test, which recommended that I pursue something which focused on three-dimensional design. It felt as if it had been written in the stars.

I phoned my dad and said: “This is it! I know what I want to do!” I sat my entrance exam and was accepted. I’m so happy I pursued it because I managed to achieve a cum laude for both my diploma and my B Tech degree. I definitely found my passion.

What is your favourite piece that you’ve designed?

My favourite design is a concept collection I created. I conducted a study about the history of jewellery in southern Africa and the symbolism used in beadwork captured my interest. Colour plays an important role in the purpose of an item, for example, siNtu-speaking cultures are well known for codified beadwork squares sometimes called _amabheqe_, where a special message is encoded by not only the relations between geometric forms, but by the relations between the choice of colours in the piece, with each colour having a contextual meaning.

I learnt about a writing system called _Ditema tsa Dinoko_, which was a linguistic extension of the traditional _litema_ and _amabheqe_ art. The writing system has the ability to represent the full phonological range in all of the siNtu languages of southern Africa. I had the privilege to work with Pule kaJanolintji, who helped me transcribe a word into the writing system. We translated “together” into Sesotho languages as _Mmogo_. When transcribed into Ditema tsa Dinoko, it became the central motif in the collection.

The colours I chose were red, green and blue, all colours that communicate the deep compassion we have to offer other nations, for we have seen the future and we are the future.

What has been the highlight of your jewellery career?

Winning the De Beers Shining Lights Award in 2015. Other stand-outs were making a bespoke piece for Idols judge Somizi to wear while hosting the SA Music Awards in 2018, being commissioned by friends of swimming champion Cameron van der Berg to make a tie-pin to take with him to the Olympics in 2016 and having my sister, comedienne Nina Hastie, wear largescale neckpieces from my 2017 B Tech collection at the SUNMET Horse Races.

Why did you decide to enter the De Beers’ Shining Lights Awards?

De Beers has always done a great job at promoting the competition through the TUT. Once the brief of the competition was sent out to all the institutions, we were fortunate enough – because of our amazing lecturer, Nina New-