Carats, Karats, and Carrots
Carat is a measure of weight for precious stones, like diamonds.
Karat is a measure of gold purity.
Carrot is something you eat.
They are all pronounced the same way, but they mean different things.
What is a carat?
Carat is a weight measure used for precious stones. There are five carats in a gram, so each carat is two tenths of a gram. A five carat diamond weighs about the same as a one dollar bill. Diamond weight is sometimes expressed in “points.” One hundred points is one carat, 10 points is a tenth of a carat, and so on.
What is a karat?
Karat is a measure of gold content. 24 Karat gold is pure gold. 12 Karat gold is an alloy , meaning that half the metal is pure gold and half is some other metal (usually a mix of silver and copper and smaller amounts of other metals). 18 Karat gold is 18/24 or three-fourths pure gold with the other fourth made up of other metals. An alloy is a mix of metals.
To find the percentage of pure gold in a piece marked in karats, divide the karat number by 24. Thus, 14K is 14/24 = .583 pure gold, .417 something else. A 14K piece has 58.3% gold in it. The rest is something else, such as silver, copper, nickel, zinc, etc.
To find the weight of pure gold is in a piece of jewelry, weigh the piece and multiply by the fraction of purity indicated by the karat mark. For example, a ring that is marked 14K weighs 30 grams, so the gold content is .583 times 30 = 17.5 grams gold, with the rest something else.
To find out how much that is worth on the gold market, go to www.kitco.com and find the current value.. Today, August 15, 2011, gold is 1739 dollars per ounce. One ounce (troy weight, see below) = 31.1 grams. Using the example above where you found the weight of gold to be 17.5 grams, divide 17.5 by 31.1 to find the fraction of an ounce that represents. Thus, 17.5 divided by 31.1 = .562 ounces. Multiply that number by the gold price to find the market value of the gold in the piece: .562 times 1739 = 977.32 dollars.
Troy weight is is used for precious metals like gold. Avoirdupois weight is for carrots. One ounce troy = 31.1 grams. One ounce avoirdupois = 28.35 grams. There are 12 troy ounces in a troy pound. There are 16 avoirdupois ounces in an avoirdupois pound. Although you can see that there are different definitions of an ounce, a gram is a gram is a gram. One thousand grams is always a kilogram. One kilogram is approximately 2.7 pounds troy and 2.2 pounds avoirdupois.
Another common weight unit for gold is the pennyweight: there are 20 pennyweights in a troy ounce, so 20 pennyweights (abbreviated dwts) equals 31.1 grams. Divide 31.1 by 20 to find grams per pennyweight (1.55 gm per dwt) or 20 by 31.1 to find pennyweights per gram (.643 dwt per gm). Pennyweights are not used for silver, but they are for platinum and palladium (as well as gold.)
Stamping: By law, items made with precious metals (like gold, silver, platinum) must have a karat mark, made by a special stamp. Karat stamps can be bought by anyone at a supplier of jewelry tools such as Rio Grande. They can be used to stamp any kind of metal, so just because something has a karat mark doesn’t mean that it is necessarily what the mark indicates. By law, the mark has to be accompanied by another mark, indicating who made the item, so you know who to blame if there is a discrepancy. Even so, there have been cases of “skimming” or “underkarating,” especially by foreign suppliers since their items are rarely tested for gold content. The basic rule is to know your supplier. In that area, the best bets are small producers — independent artists — like me.
Types of Gold:
When you’re considering a purchase of gold jewelry, it’s easy to get confused by the many descriptions that include the word “gold.” Here’s what the most common phrases actually mean:
Gold Filled, also called Gold Overlay, refers to a layer of at least 10-karat gold that has been permanently bonded by heat and pressure to one or more surfaces of the underlying metal (such as brass) then rolled or drawn to a prescribed thickness. The karat gold weight must be at least 1/ 10 of the total weight. This type of gold might be stamped 1/10 10K GF.
Gold Leaf is usually pure gold metal that has been pounded into paper thin sheets.
Gold Colors:
Pure gold has a characteristic color that is unmistakable and unlike anything else. When alloyed, gold can take on a number of colors, including: white, pink, green, and even purple.
Yellow gold is gold alloyed with varying percentages of silver and copper plus smaller amounts of other elemental metals like zinc, at times. It is the most frequently used type of gold.
White gold is alloyed with a large percentage of silver, or a selection of other white metals, typically nickel. White gold is highly reflective and does not tarnish. The ancient term for it was Electrum. Its use predates that of Palladium and Platinum. A relatively new white gold is made with alloys of palladium instead of nickel. Since some people are allergic to nickel, this is a welcome addition to the family of alloys. Ricco uses palladium white golds exclusively and never plates on top of them.
Rose gold is made by alloying gold with copper, a red metal, and silver. The more copper in the alloy, the redder the color.
Polishing Brass and Copper
Gold and silver prices have been soaring lately, so many artists are making items with less costly metals like brass and copper. When new and brightly polished both of these metals are beautiful, but with exposure to the elements, luster fades and the surface can become less attractive.
How long it takes for the original luster to fade depends on a number of things, but air quality is an important element. Smog, for example, usually contains a high amount of sulfurous components which interact with metals to form tarnish.
To get the shine back requires the piece to be polished anew. A liquid polish for this is called Brasso and it can be found in many grocery store cleaning products aisles. First apply the liquid to a cloth and then rub the metal with the cloth until the shine appears, then rinse in soapy water. The process can be somewhat messy and the cloth will turn black, so you might want to use gloves.
Another product is called Tarni-shield from 3M which has the advantage of protecting the metal from tarnishing quickly, but sooner or later you’ll have to repeat the process no matter what product you use. You can get this product from Amazon. If your jewelry tarnishes quickly, the 3M product will probably be advisable because the shine will last longer.
Another tip is to seal your jewelry in plastic zip bags when in storage. 3M makes paper strips that help prevent tarnish that you can put in to the bag along with your jewelry. Find them here.
When considering a purchase of brass or copper jewelry, keep in mind that the piece will need to be maintained in order to keep the shine (unless it has be lacquered or treated in similar manner.) Be aware that pieces with intricate details will be harder to polish, while jewelry with simple shapes will be easier.
Or you can simply let the metal acquire an overall “antiqued” look which might take time but can result in a pleasing patina. How long this takes depends on air quality where you live, but if your items tarnish quickly you might consider letting them go and see if you like the result. I recommend that you try this with an item that is not your favorite, however, because tarnish can be very hard to remove once deeply established.
Contact me if you have questions.
Ricco is Back!
It has been a while but Ricco is now back at the bench and making new designs.
I will be posting pictures soon, so keep in touch.
Thanks, Ricco




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