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Gold Jewellery 9 or 18ct

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    Gold Jewellery 9 or 18ct

    If you were buying a present for your partner what would you consider
    20
    9ct
    10.00%
    2
    18ct
    30.00%
    6
    Platinum
    45.00%
    9
    Costume Jewellery
    15.00%
    3
    How fortunate for governments that the people they administer don't think

    #2
    9ct will do just fine!
    Picolo

    Comment


      #3
      Platinum??!! No bling factor if you got to tell everyone this is really platinum, not costume jewelry! From anything further than six feet away only threaded can tell the difference!

      Gotta be gold. 18 carat is more expensive and wears out quicker, so the obvious choice for both of you is to get 9 carat.

      Sorted.

      Comment


        #4
        I would probably buy her the Costume Jewellery.

        Because she's worth every penny of it.

        Comment


          #5
          Platinum or titanium - both are really hard to damage and keep their shininess. Platinum should normally have one or more diamonds set in it so you shouldn't have to explain anything.

          Comment


            #6
            Lizzie Duke

            Comment


              #7
              Platinum is fine but it doesn't have the status attached - although I never saw the point of "white gold" either

              Comment


                #8
                Originally posted by stackpole
                Gotta be gold. 18 carat is more expensive and wears out quicker, so the obvious choice for both of you is to get 9 carat.
                I think that is an Urban Myth
                Q: Is it correct that 9 carat gold is harder wearing than 18 carat gold?
                The simple answer is no!

                Surprised?
                Most people are surprised to hear this, because for some reason, they have always believed, or been told, that 9 carat gold is harder, or harder wearing than 18 carat gold. We sometimes have trouble convincing them, sometime they will not believe us until they see it in writing. That is why we have put it in writing, and included it in our leaflets and sales literature for some years now.
                Why then does everybody tell you that 9 carat is harder?
                What we have wondered for many years, is how and why people get to believe that 9 carat is harder. I believe there are two reasons why this myth has become established:-

                * Sales Staff
                Firstly, sales staff in jewellery stores do not always know their facts, and because 9 carat gold is more commonly stocked in Britain than 18 carat, they try to sell what they have in stock, therefore it is tempting to sell the benefits of 9 carat gold. I believe that staff in many multiple jewellers have long done this, probably out of ignorance; hopefully things are changing.
                * The Obvious Assumption is Wrong
                Secondly, it is fairly well known that pure gold is quite soft, too soft, in fact to be used successfully in jewellery. This is quite accurate, although in some cultures, consumers prefer pure gold jewellery, but it is rather soft, so needs to be made quite solid for greater strength, and this adds to the price. Pure gold jewellery also would need to be worn with more care than alloyed gold jewellery. It is also fairly well known that if gold is alloyed with other metals, it becomes harder. Where many people make a mistake is to assume that the more "other" metals are added, the stronger and harder the resultant alloy. This is an easy and understandable mistake to make, and I believe that both consumers and many working within the jewellery trade have commonly made the same mistake over a long period of time, until the mistake has become lazily accepted as the truth.

                Is there a more complete answer?
                As usual, the answer to a simple question is not always simple.
                First, there are many different combinations of metals which can be used to make gold alloys. There are many different "recipes" for both 9 carat and 18 carat gold alloys. A carat simple means 1/24th, i.e. one part in 24. So 9 carat gold must be at least 9 parts gold out of 24, which is equivalent to 37.5%, the other 62.5% can be any other metal, the commonest used being copper and silver, but nickel, palladium, zinc, and other metals are used. Similarly with 18 carat gold, which has to be 18/24, equivalent to 75% gold, the rest being composed of any other metal. You would be quite correct to guess that each different "recipe" has its own different characteristics including hardness. It is quite possible to make hard or soft "recipes" for 9 carat and also for 18 carat and other gold alloys. In general, most common 18 carat gold alloys are both harder, and harder wearing than their 9 carat equivalent.

                Durability
                This brings is to the point that hardness and durability are not one and the same thing. To give a simple example, a glass ball is harder than a rubber ball. Try throwing each onto a hard surface. The glass ball will break, but the rubber ball will bounce at remain intact, because the rubber ball is more durable than the glass one. The glass ball breaks because it is brittle. In the same way, metal alloy can also be brittle, and 9 hard carat gold alloys tend to be slightly brittle, whereas 18 carat gold alloys tend to be more resilient.

                Tarnish Resistance
                18 carat alloys are almost completely resistant to chemical attack in normal use, whereas 9 carat alloys are much less resistant. Nine carat alloys for example will go dull or even black merely from exposure to chemicals in the atmosphere, they will also discolour in contact with perspiration, some fabrics, bleach and other household chemicals.

                Metallurgy & Alloys
                To understand more fully, a little metallurgy is necessary. Each and every pure metal will have a particular hardness which will not vary much. If it is worked by rolling, stretching, bending, hammering, or other mechanical process, it will tend to become harder but more brittle. It can usually be annealed or softened by heating it. Two or more metals mixed together form an alloy. Alloys differ form pure metals, in that they often combine some of the mechanical properties possessed by their constituent metals, but often also in other less predictable ways. Many alloys for example can be hardened or softened by appropriate heat treatment. Heat treatment include heating to a variety of high or low temperatures for long or short periods of time, followed by cooling at different rates. Each alloy will have different hardness figures depending on its state. Common states to be considered include:- as cast, after casting and annealing, after age hardening (heat treatment), after cold working, after cold working followed by stress relieving, and others.

                Hardness Table for Carat Gold Alloys
                Although, as we have explained, there are many different alloy "recipes", to give you an indication of the hardness figures for 9 and 18 carat golds, the following table gives a range of typical "Vickers" hardness values for fairly common "recipes":-

                Alloy Hardness as Cast Maximum Annealed Hardness
                9 70 to 105 160 to 170
                14 125 to 165 150 to 180
                18 85 to 125 170 to 230
                22 70 60 to 90
                23.75 40 70
                Silver 65
                Platinum SC 65
                Platinum HC 135

                Key to Table
                Silver = Typical sterling silver (925/1000)
                SC = Soft casting alloy
                HC = Hard casting alloy
                How fortunate for governments that the people they administer don't think

                Comment


                  #9
                  Originally posted by Picolo
                  9ct will do just fine!
                  Hi Lucy
                  How fortunate for governments that the people they administer don't think

                  Comment


                    #10
                    Gotta be diamonds

                    Gold smold - buy expensive stones and they appreciate in value buy gold and all you've ever got is scrap value unless its a bar of course.

                    Comment

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