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Frequently Asked Questions About Pearls


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Freshwater vs Saltwater

"Q"......"what is the difference between Freshwater and Saltwater pearls"........

"A"......... On the face of it this is an easy question to answer ... Freshwater pearls are grown in "Mussels" and Saltwater pearls are grown in "Oysters". But you may need to know more; in fact, the mussel and the oyster are related bivalves, however, the "Mussels" used to produce freshwater pearls are larger than the delicious black and blue edible type we associate with "Steamed Mussels" and the" Oysters" used in saltwater pearl production are 'dinner plate' size and are not the edible type we are so fond of. Chemically speaking the fresh and salt water pearls are almost identical with the difference being in trace elements found respectively in the two different types of water the animal grew up in and this can be used to identify the difference but this is a destructive and expensive laboratory test. Up until recently the way to tell the difference in the two types of pearls was by elimination and experience, "are the pearls large, over 9mm in diameter?", indicating saltwater, or by colour, shape and surface texture.

Freshwater Pearls

Cultured freshwater pearls are "Mantle Nucleated" this means that the growth process that builds the pearl starts with a small piece of live mantle tissue that is placed in an incision in the body of the growth animal, where the "Epithelium" cells, present on the mantle tissue, do their job of excreting saliva that solidifies into "Nacre" or "Mother of Pearl" many of these implants can be carried out on each animal thus producing multiple pearls from one mollusc. The pearl is built layer by layer for as long as the animal is left alone getting larger and larger as the years pass, or more likely, the pearls are harvested for sale, or finally, the host animal dies.

Saltwater Pearls

Saltwater pearls are not "mantle nucleated" and can only support one pearl per oyster, they are "Bead" or Seed Nucleated" this is where a small "Bead" is implanted in the animal's body along with the essential "Epithelium" cells (live mantle tissue) who continue to do their genetic duty and produce "Nacre" this time it is the Bead that is coated and a pearl starts to grow layer by layer. (special beads are used to seed the oyster and are critical so as not to be rejected by the animal.) Therefore, it was basically the size of the pearl that gives the biggest clue as to the origins of this wonderful gem. However, this is no longer necessarily true as techniques have moved on and science has produced a Freshwater cultured pearl that is both large and "Bead" nucleated, and at least for the time being, is necessarily expensive and probably not the quality of the Saltwater variety. We expect producers to gain expertise in farming methods, narrowing the quality and size gap between fresh and salt water pearls. We will try and keep informed of these developments.

"Akoya" Saltwater Cultured Pearls

In order not to confuse you, we have delayed mentioning the Saltwater Cultured "Akoya" pearl grown by the oyster Pinctada Chimnitsii and martensii. These pearls are both small 4-7mm in diameter and "bead" nucleated. Fortunately they are distinct for their round shape, white colour with a hint of rose overtone and clean surfaces, much favoured by discerning buyers and Japanese clients. "Akoya" pearls, sometimes mistakenly called "Japanese Pearls" were made famous by "Mikimoto" who developed early culturing of pearls, the Akoya is grown in cooler water and this produces a slower growth and denser pearl when compared with their saltwater cousins - faster growing Saltwater cultured pearls that are grown in warm tropical water.

Where to Sell Old Pearls

"Q"...... "My Mum left me some pearl jewellery that I want to sell"........

"A".........Pearl Magpie does not deal in pre-owned pearl jewellery as we need to know the origins of our pearls. It therefore follows that we do not give valuations for pearl jewellery we have not sold.
Before embarking on the expensive testing of your pearls try this first:
Indications of value will be the type of setting used, is it "hallmarked", is it 'heavy' and does it contain 'Diamonds' or other precious gems, and lastly does the jewellery come in a 'branded' and custom fitted box?

As for the pearl or pearls, it is generally possible to tell the difference between imitation pearls and genuine pearls - the surfaces of imitation pearls are too uniform and may be said to be “too good to be true” and are smooth to the “tooth”, there may also be a difference in weight and “coolness” to the feel.
However it is not as simple to tell the difference between
• Natural Pearls and Cultured Pearls and also between
• Saltwater Cultured Pearls and Freshwater Cultured Pearls.

For accurate evaluation of pearls, laboratory equipment must be used, from high powered Microscopes, to X-Ray equipment, it therefore follows that this is an expense that may not be warranted by the value of the pearls alone.

It is possible for a specialist to give qualified opinions, the weight of which would be commensurate with their experience and in consideration of the “clues”. These clues include nucleation, shape, colour, size, non invasive tests and provenance. Indeed if the conclusions came from a reliable source then it would normally be accepted as accreditation for “Valuation for Insurance” or even for sale value.

Pearl Magpie recommends:

The BJA British Jewellers’ Association
Federation House
10 Vyse Street
Birmingham B18 6LT
Tel: 0121 237 1110
Fax: 0121 237 1113
http://www.bja.org.uk/

 

The National Association of Goldsmiths' Institute of Registered Valuers
78a Luke Street,
London EC2A 4XG
Tel: 020 7613 4445
http://www.jewelleryvaluers.org/
irv@jewellers-online.org

We can also suggest that if the Pearl Jewellery is thought to be valuable then the opinion of a reputable Auction house should be sought.

http://www.bonhams.com/
http://www.christies.com/
http://www.sothebys.com/en.html

It might also be an idea to take your jewellery to a Pawn Broker who will have to value it for the purposes of a loan and this might help you. Further, a price may be suggested from any number of “Antique” Markets whose business it is to buy and sell pre owned items.
In London we have:

www.alfiesantiques.com/
www.portobelloroad.co.uk/
www.graysantiques.com/
www.oldspitalfieldsmarket.com/

Ultimately, Common sense and knowledge will guide you in establishing the value of your item. Good luck and should you require further information then please call us and we may be able to offer further help.

Keshi Pearls

"Q"......"What are Keshi Pearls"........

"A"........Keshi Pearls can be either Freshwater or Saltwater pearls but are only nucleated by epithelium cells resulting in very small pearls being produced with pure nacre (mother of pearl). The resultant keshi pearl, though small in size, is generally very high in lustre and when colour treated, can possess extra ordinarily beautiful colours. read more about their formation here

Gold Plating

"Q"......"What is Gold plating"........


"A".........From Wikipedia, the free encyclopaedia

Gold plating is a method of depositing a thin layer of gold onto the surface of another metal, most often copper or silver (to make silver-gilt), by chemical or electrochemical plating. 

Gold plating of silver is used in the manufacture of jewellery. Like copper, silver atoms diffuse into the gold layer, causing slow gradual fading of its colour and eventually causing tarnishing of the surface. This process may take months and even years, depending on the thickness of the gold layer. A barrier metal layer is used to counter this effect. Copper, which also migrates into gold, does so more slowly than silver. The copper is usually further plated with nickel. A gold-plated silver article is usually a silver substrate with layers of copper, nickel, and gold deposited on top of it.

In Summary: Gold plating of less precious metals keeps the price down but is an effect that will wear off in time and frequent use, due to its very thin coverage.

Gold Vermeil

"Q"......"What is Vermeil"........


"A".........From Wikipedia, the free encyclopaedia

Vermeil (/ˈvɜrmɪl/ or /vərˈmeɪ/; French: [vɛʁˈmɛj]) is an alternative for the usual term silver-gilt, or silver plated or gilt with gold. Vermeil pieces appear to be gold but are less expensive and lighter than solid gold. It is a traditional luxury material used for table plate, toilet services and grand decorative pieces. “Vermeil” is a French word which came into use in the English language, mostly in America, in the 19th century, and is rare in British English, it is a combination of sterling silver, gold, and other precious metals, commonly used as a component in jewellery. A typical example is sterling silver coated with 14 carat (58%) gold. To be considered vermeil in the US, the gold must be at least 10 carat (42%) and have thickness equivalent to at least 2.5 micrometers of fine gold (a 12 carat [50%] plating would need to be 5 μm thick).

Vermeil can be produced by either fire-gilding or electrolysis. The original fire-gilding process was developed in France in the mid-18th century; however, France later banned the production of vermeil because over time artisans developed blindness due to mercury involved in the process. Today, vermeil is safely produced by electrolysis.

The US Code of Federal Regulations 16, Part 23.5[2] defines Vermeil: "An industry product may be described or marked as 'vermeil' if it consists of a base of sterling silver coated or plated on all significant surfaces with gold or gold alloy of not less than 10 karat fineness, that is of substantial thickness and a minimum thickness throughout equivalent to two and one half (2½) microns (or approximately 1/10000th of an inch) of fine gold."

In Summary: Vermeil Gold is thicker than conventional Gold plating and helps to keep the cost down as compared to solid gold. It is generally used to gold plate Silver to increase its value but must be of sufficient precious metal content to qualify as “Vermeil Gold”

Gold Filled

"Q"......"What is Gold-filled jewellery"........


"A".........From Wikipedia, the free encyclopaedia

Gold-filled jewellery is composed of a solid layer of gold, which must constitute at least 5% of the item's total weight, mechanically bonded to sterling silver or a base metal. The related terms "rolled gold plate" and "gold overlay" may be used if the layer of gold constitutes less than 5% of the item's weight. 

Some high quality gold-filled pieces have the same appearance as 14 karat (58%) gold. Gold-filled items, even with daily wear, can last five to 30 years but will eventually wear through. Gold-filled items are 50 to 100,000 times thicker than regular gold plating, and 17 to 25,000 times thicker than heavy gold electroplate (sometimes stamped HGE or HGP—usually found on cubic zirconia "cocktail rings").

Definition

In the United States, the quality of gold-filled is defined by the Federal Trade Commission (FTC). If the gold layer is 10 kt fineness, the minimum layer of karat gold in an item stamped GF must equal at least 1/10 the weight of the total item. If the gold layer is 12 kt or higher, the minimum layer of karat gold in an item stamped GF must equal at least 1/20 the weight of the total item. The most common stamps found on gold-filled jewellery are 1/20 12kt GF and 1/20 14kt GF. Also common is 1/10 10kt. Some products are made using sterling silver as the base, although this more expensive version is not common today. These standards are for modern gold-filled items. It is not uncommon to see 1/8 14kt gold-filled marks, plus many other variations, on items from the 1930s, 1940s, etc., which would have to be marked "Rolled Gold Plate".

The FTC allows the use of "rolled gold plate," "R.G.P" or "gold overlay" on items with lower thicknesses of gold than are required for "gold-filled."

In Summary: Gold-Fill jewellery is that jewellery made with material whose outer surface is gold bonded to the inner material and represents more that 5% of the whole weight of the piece. This is another way to keep the cost down from solid gold but is more expensive than Gold Plating and Vermeil and it affords the longest wear for frequently used jewellery but not as much as solid gold.

Rhodium Plated

"Q"......"What is Rhodium Plating"........


"A".........From Wikipedia, the free encyclopaedia

Rhodium, used in jewellery and for decorations, is electroplated on white gold and platinum to give it a reflective white surface at time of sale, after which the thin layer wears away with use. This is known as rhodium flashing in the jewellery business. It may also be used in coating sterling silver to protect against tarnish, which is silver sulphide (Ag2S) produced from the atmospheric hydrogen sulphide (H2S). Solid (pure) rhodium jewellery is very rare because the metal has both a high melting point and poor malleability, making such jewellery very hard to fabricate — rather than due to its high price. Additionally, its typically higher cost assures that most of its jewellery usage is in the form of tiny amounts of powder, commonly called rhodium sponge, dissolved into electroplating solutions.

Rhodium is a chemical element with symbol Rh and atomic number 45. It is a rare, silvery-white, hard, and chemically inert transition metal. It is a member of the platinum group. It has only one naturally occurring isotope, 103Rh. Naturally occurring rhodium is usually found as the free metal, alloyed with similar metals, and rarely as a chemical compound in minerals such as bowieite and rhodplumsite. It is one of the rarest and most valuable precious metals.

Rhodium is a noble metal, resistant to corrosion, found in platinum- or nickel ores together with the other members of the platinum group metals. It was discovered in 1803 by William Hyde Wollaston in one such ore, and named for the rose colour of one of its chlorine compounds, produced after it reacted with the powerful acid mixture aqua regia.

The element's major use (approximately 80% of world rhodium production) is as one of the catalysts in the three-way catalytic converters in automobiles. Because rhodium metal is inert against corrosion and most aggressive chemicals, and because of its rarity, rhodium is usually alloyed with platinum or palladium and applied in high-temperature and corrosion-resistive coatings. White gold is often plated with a thin rhodium layer to improve its appearance while sterling silver is often rhodium-plated for tarnish resistance.

In Summary: Rhodium plating in jewellery terms is the plating over of precious metals to enhance the brilliance and increase the longevity of the precious metal beneath. as it is an electroplating process ,the coverage is very thin and will wear off in the shortest time of all the plating methods, however, re plating is not an expensive alternative to keep the ‘shine’ on your jewellery and is non destructive when compared with ‘Polishing’.