How to choose?
First of all we need to distinguish between jewellery and fine gold articles: jewellery means objects in gold or platinum with embedded precious stones and/or pearls; fine gold articles are objects in gold, with or without enamels, not printed in series.
A diamond is carbon crystallised millions of years ago and its extreme hardness is due to the grouping of carbon atoms. To assess the quality of a diamond we need to take into consideration 4 factors:
Colour: colour variations range from almost total absence of colour to light yellow. The exact classification of the colour of a diamond in one of the imperceptible varieties of tone, is fundamental in determining its value. The rarest diamonds are almost perfectly white. When the colour tends to yellow the price of the diamond is lower.
Purity: most diamonds present a certain number of inclusions or blemishes. The assessment is carried out taking account of the number, type and position of these impurities, which are divided into features (light marks) and carbon spots (dark marks).
Carat weight: the weight of diamonds is expressed in “metric carats”. One metric carat is equivalent to 0.20 grams.
Cut: this is fundamental for the stone to liberate all the light it is capable of. In the cut however a notable part of the rough stone is lost (about a half). This is a very delicate operation: the gemcutter’s ability consists in fact of identifying the facets with absolute precision, so as to cut at the right point. It is worth remembering that perfect cutting of small stones requires a larger quantity of labour, in proportion, than that necessary for large stones; this explains the sometimes high price of small but pure and well-cut stones.
Ruby and Sapphire:
Ruby and Sapphire belong to the corundum family. Corundums are aluminium oxides, which in nature are found in the form of crystals of various colours: the most precious varieties are red (rubies) and blue (sapphires). These two stones, which are very different in appearance, are twin sisters, with the same chemical composition and the same characteristics.
Rubies may often present signs, impurities, small clouds or the typical “silk” formed by inclusions of tiny needles of rutile. The colour range is quite wide (from purplish pink to deep red). The best is considered the “pigeon blood” red, very bright and intense, typical of rubies from Burma.
Sapphires are much more common than rubies, and therefore less expensive. The most precious are of an intense, deep, velvety blue. The best sapphires come from Kashmir (although now the mines are exhausted or inactive) and present a very precious cornflower blue colour. Most of the current production of sapphires comes instead from Burma, Siam and Ceylon. The sapphires of Ceylon often have a lighter hue tending slightly to purple. Very dark, almost black, sapphires come from Australia.
Emerald is a beryl, that is, chemically, a silicate of aluminium and beryllium. The emerald is not as hard as ruby and sapphire. It is a relatively fragile stone, to be treated with great care. For clearer emeralds, the traditional cut is the wide table cut, in a square or rectangular shape. This is the so-called “emerald cut”, much used also for other clear stones of a beautiful colour (aquamarines, amethysts, topazes, diamonds). Emeralds come mainly from South America.
The technique of classical culture in seawater molluscs involves inserting a mother-of-pearl sphere inside the shell. The mollusc defends itself against the intruder covering it with concentric layers of nacre. One of the qualitative parameters that contributes to the value of a pearl is the thickness of the layer of nacre around the mother-of-pearl nucleus. Of great importance is also the surface of the pearl, which must be free of irregularities, colour differences and other evident defects. A high-quality pearl should be iridescent and not opaque. The colours and shades are very varied and here too the choice depends on personal taste and on the type of jewel it is intended to be used for. The great rarity and the difficulty of harvesting natural pearls makes them much more precious than cultivated pearls.
Fred Samuel was born in Buenos Aires in 1908, as the son of a Lorraine jeweler who emigrated to Argentina. He spent most of his professional life in Paris, but the South America lights were with him, inspiring every labor element of his the life.