Information and jottings about about precious metals, jewellery and style.
More information will be added over time
carats explained about silver birthstones plating history
Carat is a statement of the purity of gold and whilst this would most commonly be used in conjunction with solid gold the same applies to plate. Plate, however, has not been assayed and carries no marks so a degree of trust has to take place. The explanations apply to United Kingdom carats as carats are not always equal around the world. When the fineness of gold is mentioned it is indicating the same value as carat.
The carats of gold allowed to be used in this country, for jewellery, are 9, 14, 18 and 22 with the UK being very strict as to what those numbers indicate. 24carat gold is, theoretically, 100% pure gold but a very slight tolerance is allowed. So 24 carat gold can be 99.9% but no lower. Therefore, 18 carat gold is 18/24ths of pure gold and so on down the numbers. The difference is made up of other alloys which enables the different colours of gold to be achieved, rose, white, green etc. With 9 carat being 9/24ths of pure gold it contains the most alloys which allows the greatest range of colours of the metal.
Fine silver, 99.9% pure such as that used in bullion bars, is a very soft metal so for practical use is mixed with an alloy like copper. Typically in sterling silver this is 92.5% silver, which can not be lower for hallmarking, and 7.5% copper and can be recognised by the symbol of the lion passant in England, lion rampant in Scotland and the crowned harp in Ireland.Britannia silver is 95.8% pure and is usually found amongst older pieces of silverware. Britannia silver can be recognised by it being stamped with the symbol of Britannia and the 958 stamp since 1999.
Whilst silver is a beautiful metal it can scratch
easily and is prone to tarnishing due to sulfur in the
air. To clean silver Precious Metal Plating use
Goddard's silver polish.
Silver other than British very often has a lower (much
in some cases) silver content and is usually described
as white metal or Indian silver (or whatever country).
This is not necessarily a bad thing for example silver
mixed with 40% palladium is said to have a better
resistance to tarnishing.
Soon you will be able to buy jewellery items from PMP containing birthstones which means that you can keep this handy for reference.
January
Garnet. Said to have protective and regenerative powers
garnets can come in various colours: shades of
green, burgundies, reds, oranges and yellows.
Rose Quartz. Some would say that the brilliant, pink,
rose quartz is a natural healer.
February
Amethyst. Beautiful purple colour it is said to prevent intoxication and give protection when you go into battle.
Onyx. Black onyx is believed, by some, to aid self control and help with stress.
March
Aquamarine. Can be found in pastel blues and greens. A
hard gemstone good for jewellery.
Serenity, understanding, peace and love are some of the
qualities associated with aquamarine.
Bloodstone. Dark green stone dotted with red spots often used, in medieval times, for carvings of the crucifixion .
April.
Diamond. Most of the worlds gemstone market is in diamonds promoting love, courage, strength and healing. However if diamonds are out of your reach you will have to settle for rock crystal.
May
Emerald. Green with yellow or blue hues, depending on where mined, it may improve your memory and spiritual awareness.
June
Alexandrite. Looks green in sunlight and red/violet under artificial light it is the next expensive gemstone to the diamond.
Pearl. Well you know the colour of pearls suffice to say that if you have a perfectly round one be very suspicious.
July
Ruby. Lucky those born in July to have the beautiful red ruby the colour of which can change in intensity and is said to be able to predict the future.
August
Peridot. Fresh lime green in colour peridot is an affordable gemstone that some believe will help with wealth, health and sleep.
September
Sapphire. Commonly blue but also come in orange, pink, yellow, red, purple and greenish blue. Sapphires are said to help you overcome a challenge.
October
Opal. Primarily found in dry outback desert the opal can have all the colours of the rainbow and then some. Could help with you mystic powers giving you protection.
Tourmaline. Found in a variety of individual and multi colours. This gemstone should help with your inspirational powers.
November
Topaz. Foundin yellow (most common), yellow brown, honey yellow, flax, brown, green, blue, light blue, red and pink, sometimes it has no colour at all. May help to give protection against your enemies.
Citrine. The most popular colour of citrine is yellow (lemon). Help to dispel your sadness on a bleak November day with the glow of a citrine.
December
Turquoise. The sky blue turquoise, when worn, is said to make you aware of impending doom by changes in its colour.
Tanzanite. Blue with a hint of purple give tanzanite a uniqueness. Very rare and expensive, stick with turquoise.
Zircon. Found in a range of colours the most common of
which is blue. It is said to help with insomnia could
also bring you wealth and wisdom. back
to top
The middle classes, and their increasing prosperity, have always been the driving force for commerce and industry and the desire for betterment has been the reason for a lot of innovation worldwide. They might not be able to afford a lot of the very best but if you can give them something that is nearly there and less expensive then profit is to be made. It was this desire that led to the earliest form of plating in the 18th century.
In approximately 1770 a method of fusing a sheet of silver to both sides of a sheet of copper was developed which was then made up into various ornamental pieces. Originally the plate was only on one side so the inside of a vessel would remain copper.
Items produced by this method are known as Sheffield Plate there are, however, a number of problems with this method of plating. Edges, such as the rim, would show the copper middle. Various methods were used to hide this core for example: a u shaped wire could be placed over a rim to disguise the edge and over time these lips became ornamental. Do not assume, however, that a piece you may have with a pronounced lip is Sheffield Plate as later pieces were cast, made, with this effect.
Engraving Sheffield Plate was also a problem as it revealed the copper core. To overcome this a section of much heavier plate or pure silver could be let into the piece to take the engraving, say, of a coat of arms.
By the 1850's Sheffield plate had all but disappeared being superseded by electroplating which was invented in the 1840's. Electroplating gave the public the beauty of silver at an even less expensive price than Sheffield Plate.
There are a number of claimants (my thinking, refs. Luigi Galvani in the 1700's) to the invention of plating by electrolysis but going with convention it can be said that Elkington (of Elkington Co.), from a collaboration with John Wright, took out a patent for the depositing of silver by electrolysis in 1840. Those principles are carried on till this day with slight variations here and there. The big advantage of electroplating is cost and the fact that you can engrave prior to plating.
You may come across the term filled gold or rolled gold (essentially the same though some would say different) which is a type of gold plating similar in process to Sheffield Plate. Popular since the 1860's the main advantage is that it is a thicker layer than plated and has a greater wear property than electro plating. back to top