The leaves on the end are smaller in stainless steel sparks. Steel made with less carbon produces yellow sparks with different lengths. The leaves on the end fan out more with a lot of extra little branches. Steel with high amounts of carbon produce sparks that begin spreading out near the grinding wheel. The sparks are duller or even red and fan out less at the end. Some metals, including nickel and aluminum, produce few or no sparks.
Include your email address to get a message when this question is answered. The best way to learn how to identify steel is to practice on pieces you are already familiar with. Helpful 0 Not Helpful 0. Steel consists of a combination of other elements. These combinations vary widely, so knowing exactly which type of steel you have is difficult. Helpful 1 Not Helpful 0. Submit a Tip All tip submissions are carefully reviewed before being published. Always take safety precautions when breaking or grinding metal.
Helpful 4 Not Helpful 1. Related wikiHows How to. How to. About This Article. Co-authored by:. Co-authors: 4. Updated: June 3, Categories: Steel. Article Summary X You can identify steel by several properties, like its weight, color, and magnetism. Deutsch: Stahl identifizieren. Thanks to all authors for creating a page that has been read 59, times. Did this article help you? Cookies make wikiHow better. By continuing to use our site, you agree to our cookie policy. Paul Williams Dec 19, By signing up you are agreeing to receive emails according to our privacy policy.
If the metal has a brightly colored reddish tint to it that is relatively shiny, the metal is most likely copper metal. When copper is exposed to the elements, it turns green. Look for any signs of yellow coloring on the metal. Copper and brass can often be confused with each other. Remember that copper is mostly red and brass is mostly yellow.
Look for signs of shiny, silvery colors with metals that are softer and more flexible than other metals.
If you see these characteristics, you may have aluminum. Check your metal by applying the magnet test again if you suspect that the metal is aluminum. Aluminum and tin can be mistaken for one another, but tin will stick to a magnet while aluminum will not. Tin also has a similar color to aluminum but shows a slightly duller finish. As an additional test, you can perform a file test for faster and easier metal testing.
The Heft test is related to the specific gravity of the metal. The specific gravity of a material is the ratio of its weight to the weight of an equal volume of water. The specific gravity of pure platinum is Pure gold has a specific gravity of The specific gravity of copper, nickel, brass, iron, and stainless steel are all below 9. This illustrates why base metals will feel lighter than precious metals. This is also why pure gold, for example, will feel heavier than gold alloys , which are mixtures of gold and base metals.
This is also why a platinum piece will feel twice as heavy as the same piece in silver. Base metals are magnetic; precious metal alloys generally are not. This is an easy test. Simply hold a magnet to your jewelry and check for attraction. Make sure your magnet is strong enough to provide reliable results. Good magnets can be purchased at most toy or hardware stores. Your refrigerator magnets are not likely to be strong enough to produce reliable results.
Left to right: platinum-iridium, platinum-ruthenium, and platinum-cobalt. Platinum-cobalt alloys can be slightly magnetic. Gold and most platinum alloys are not magnetic, but plated goods with a base metal foundation of iron or stainless steel will be. Remember that cobalt-platinum alloys are slightly magnetic. The Magnetism Test can provide a quick means to separate gold plated jewelry from jewelry made of karat gold. It can also separate platinum alloys lacking cobalt from ones with cobalt, which can be slightly magnetic.
An electronic gold tester. Electronic testers are a fast and easy means for detecting the fineness of your gold jewelry. They are variably priced and available at jewelry supply stores. While testers can be accurate within two karats, they cannot tell you if your piece is gold plated because they only perform a surface contact test. You can get a deeper reading by nicking your jewelry in an inconspicuous spot and taking a reading, but this is not recommended for obvious reasons. Electronic testers are easy to use, portable, and give quick results, but some may leave a small mark on items with low karatage.
Touchstone assay materials and equipment. This ancient test is used primarily for determining the fineness of gold alloys.
The touchstone test requires the use of a black basalt slab called a touchstone, nitric and hydrochloric acids, and a set of test or comparison needles with a range of precious metal finenesses. The unknown, or the metal to be tested, is rubbed on the stone leaving a streak. Never rub prongs or visible parts of a piece of jewelry on the touchstone. Always choose an area of the piece that does not show. Additional streaks are then made using the test or comparison needles; one with an estimated fineness equivalent to the unknown metal and at least two others estimated to be of lower and higher fineness than the unknown.
Rubbing gold on a touchstone for testing. The color of the streaks is compared briefly and then acids are applied to see the reaction. Higher karat gold will require the use of aqua regia. Nitric acid may be used alone for 14K and lower karat gold alloys. Compare the reactions of the unknown metal with that of the test needles. Watch for color changes and watch to see how quickly the streaks disappear. When two streaks react the same way, they have the same fineness.
The touchstone test is not suitable for plated objects such as this candlestick holder. The touchstone test is not suitable for gold filled or gold plated items. It can detect fineness of ten to twenty parts per thousand, but it does not work as well with higher karat alloys and white golds. Silver can be assayed with a touchstone, but some expertise is required because the metal used to alloy the silver can affect the results. Although the touchstone method can work with platinum, it is a challenging procedure best left to professional assayers.
There is no sure touchstone test for other platinum group metals. Touchstone testing must be done with care to get accurate results. If your results are not accurate try some of the following:. Gold testing liquid for determining 18K gold standard. Remember that is important to take precautions when using, storing and disposing acids. More information is provided in the section below on Acid Testing, but amateurs should be trained in the proper techniques before attempting these tests.
Acid testing supplies for jewelry. Acid testing is an extension of the touchstone test. It can be destructive to your jewelry so it must be practiced with care. At a minimum, you should always avoid breathing the fumes and wear gloves and protective eyeglasses when working with acids.
Acids also require specific mixing, storage, and disposal protocols beyond the scope of this webpage. The layman can apply acid tests, but only when they are properly trained.
In most cases, it would be best to have a professional do these tests for you. One of the characteristics of precious metals is their resistance to chemicals. Standard acid tests for gold and platinum are based on the fact that they will not react with pure nitric acid but they will react to aqua regia , which is a mixture of nitric acid and hydrochloric acid. Always use caution when dealing with acids.
It is possible to purchase acid testing liquids at jewelry supply stores or rock shops. If for example, you purchase a small bottle of 14K gold testing liquid nitric acid and place a drop on an inconspicuous part of your jewelry, you can observe the following reactions:. This type of analysis does not require the destruction of the sample to determine its alloy grade type.
The analysis typically takes only a few seconds to complete, and can be done with a handheld device. Since tests can be completed anywhere, it has become a very popular. This type of analysis uses Argon as a shielding gas around the spark, allowing for Carbon analysis. This method, while being more accurate than XRF or Arc sorting, is also slower as the sample needs to be prepared with a sanding disc or belt, and the analysis can take several seconds. However, this is the only method that can provide an accurate, quantitative Carbon reading.
Measuring carbon content requires training in the proper use of the equipment. If the tests are not done properly, it can negatively affect the end results of a product or determination for how to proceed with available materials.
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