Saturday, February 19, 2011

2/19/11 Report - Gold and Silver Purity & Artifacts

Treasure Coast Treasure Beach Metal Detector Find.Silver Bracelet Found on Treasure Coast Shipwreck Beach.

I showed this bracelet back in October of 2010. As I often do, I was browsing artifacts to see what I could learn. The more familiarity you have with artifacts of different time periods, the easier it will be to identify and date finds.

I happened to run across a photo of a gold chain (shown below) from the Atocha that has a clasp that is similar to the one on the bracelet. The fact that they made clasps like that during the 18th century adds information that is consistent with the idea that the bracelet might have came from the 18th century shipwreck that lies opposite the beach where the bracelet was found.

The clasp on the bracelet definitely appears to be hand made. And it shows more deterioration than the gold clasp, as would be expected.

Clasp of Gold Chain from Atocha.

You might already know how to calculate the value of your gold, but I was recently talking to some people that I thought would know this and they didn't. As a result, I thought I would pass this information along, even if a lot of you already know it.

24k (karat) gold is $100 percent gold. It is pure gold.

Most gold either has some impurities naturally or has some alloys added that dilutes the purity of the gold. You seldom find pure gold. Pure gold is very soft and alloys are added to make it harder (and cheaper), and sometimes alloys are added to change the color. With some practice you can learn to identify the approximate purity of gold without any tests, but if there are ways to test gold. One way is by using an acid test kit, that can be purchased at jewelry supply stores or other places.

Anyhow, what I wanted to say is if you know the karat value, you can calculate the value of your gold.

10K is 10/24 = 41.7% gold.
14K is 14/24 = 58.3% gold.
18K is 18/24 = 75.0% gold.
22K is 22/24 = 91.6% gold.

Most quality pieces of modern jewelry will be marked. Otherwise, if you lack an acid test kit, you can go to a jewelry store where they might test your gold for you free.

I've seen also lot of 9K gold lately for some reason. It seems to me that has been since the price of gold has increased, and therefore is probably just to make it cheaper.

Once you know the karat value and calculate the percentage of your item that is gold, then you can multiply the percent times the current spot price to get the value of your gold. If gold is at $1350 per oz. and your gold is 18K, multiply .75 times 1350 to get the value per oz. Then if you know how many ounces or fractions of an ounce you have, you can figure out the actual value of the gold.

Most gold buyers will give you a little less than the actual value. They want to make some money too, but don't take too much less. Find someone that will give you a good price.

You should also weight your item in grams and troy oz. before going to sell so you will have an idea of the weight of the item.

One error that many people make is when they see 14KP, for example, they think the P means the item is gold plated rather than pure gold. The P actually stands for "plum," not plated. 14K and 14KP, in general terms, means about the same thing.

To get a more complete explanation of plum, you can use this link.

When not having the markings or not trusting the markings, and when using an acid test kit, you'll have to scrape deep enough to get through the plating to make sure the item is not plated. You can tell "gold filled" items because the gold rubbing on the touch stone will have a milky appearance when tested.

By the way, some unscrupulous people will stamp items with the wrong karat ratings. So be careful not to simply accept the markings.

By the way, gold and precious metals are measured in Troy Ounces rather than the system we usually use to weigh groceries and the like, which are measured using what is called the avoirdupois system. There are 12 troy ounces per pound rather than the 16. As a result, an ounce of gold is actually heavier than an ounce of soup.

Gold is measured in Troy Ounces, so it is best to weigh precious metals on a scale that will give you the weight in Troy ounces.

What started out to be a very simple topic, has become a bit more complicated. That is the way it usually goes - the more you get into something the more complicated it becomes.

The silver and gold bars found on the Spanish galleons were marked for purity with what is sometimes called a "fineness" number, which was in the form of a Roman numeral expressing the purity as a fraction, with 100% pure gold or silver being 2400 of 2400. 75% gold or silver would be 1800(in Roman numerals)of 2400.

Forecast and Conditions.

The weather is simply beautiful. Just a touch of chill in the morning.

The wind is out of the northwest and the seas relatively calm. I would expect no change in conditions. Seas will be around 2.5 feet throughout the weekend. That is nothing that will change anything much.

Happy Detecting,