Prior to commencing any testing, it is essential to carefully examine the item using a jewellers loupe, as small hallmarks may not be visible to the naked eye. All gold, silver, and platinum items in the UK are required to have hallmarks.
To ensure compliance with UK regulations, hallmark charts should be displayed at all locations where precious metals are bought or sold. It is important to familiarize oneself with these markings.
Each hallmark is accompanied by a date letter that can be cross-referenced in a hallmark book containing British and international hallmarks, aiding in the dating of antique items.
For further guidance and tips, The Gold & Silver Buyer’s Handbook offers valuable information.
MAGNETIC TESTS
Gold and silver do not have magnetic properties, making magnetism a useful tool for distinguishing between genuine gold or silver items and other metals. Some metals like copper and silver are diamagnetic.
Prior to conducting tests, it is advisable to use a fine steel file on the surface to ensure accurate results. Having a specialized set of magnets for testing purposes can be advantageous.
HARDNESS / MALLEABILITY
Precious metals are malleable and can bend easily, especially high-carat gold items. Filing the surface before testing can help differentiate between gold, silver, and steel.
It is important to note that malleability and hardness are inversely related properties. While precious metals like gold are very malleable, they are not very hard and can be easily scratched or dented. On the other hand, steel is much harder and less malleable, making it more resistant to scratches and dents.
Additional Information:
It is important to follow safety precautions when using acid for metal testing, such as wearing gloves and protective eyewear. Acids should be stored in a cool, dry place and kept out of reach of children.
Using the Touchstone method involves rubbing the metal on a black stone and applying acid to the resulting streak to determine its composition.
For professional testing, specialized equipment such as an electronic metal tester or X-ray fluorescence spectrometer may be required.
It is recommended to practice on known metals before testing valuable items to ensure accuracy and proficiency in using acid for metal testing.
DE-PLATING
Overview
The KEE tester is a cost-effective option for accurately testing yellow gold, although it is limited in its ability to test white gold and cannot test for silver.
Procedure: Place the item on the test plate and touch it with the pen-probe to obtain a reading.
Advantages: Quick and easy to use, does not require the use of acids for testing.
Disadvantages: Not suitable for testing platinum or white metals, requires filing to test underneath plating.
Safety: The KEE tester is safe to use and involves harmless salt solution in the pen-probe.
XRF (X-ray Fluorescence)
Advanced testers utilize x-rays to analyze metal samples, providing detailed information on all metals present in the item.
These testers are relatively straightforward to use but require caution and proper handling for safety purposes.
Over the years, prices for testers have become more affordable, offering a convenient solution for metal testing.
SPECIFIC GRAVITY, SG (RELATIVE DENSITY)
Overview
Specific gravity testers compare the relative weight of items, helping to differentiate between metals like gold and aluminum.
Procedure: Weigh the item in air and water for small items, or use a specific gravity chamber for larger items.
Advantages: Non-destructive testing involving only water, versatile for testing gemstones and minerals.
Disadvantages: Requires precision and accurate measurements for reliable results.
This process requires meticulous and slow work, making it unsuitable for a busy shop or market stall. When weighing in water, multiple readings should be taken to calculate an average.
Availability
Specific gravity testing is commonly used in various industries such as jewelry, mining, and metallurgy. It provides valuable information about the composition and purity of materials, especially precious metals and gemstones.
Specific gravity testers come in different shapes and sizes, from handheld devices for small items to larger chambers for bigger samples. The versatility of specific gravity testing makes it a valuable tool for quality control and material identification.
When performing specific gravity tests, it is essential to follow the proper procedure and ensure accurate measurements. Any miscalculation can lead to inaccurate results and misinterpretation of the material’s composition.
Overall, specific gravity testing is a reliable and non-destructive method for determining the density of various materials, making it an essential tool for many industries.
RESISTIVITY (for coins and bars)
Overview
These testers are designed to verify the authenticity of coins and bars, rather than their purity. They assist in confirming if items are as claimed, such as a gold Sovereign or a 100g bar of 999 silver.
Procedure
Place the item on the test-plate and use the provided probe or ‘bridge’ attachment. Select the carat and alloy, then compare the reading to determine authenticity.
How it works
NON-TECHNICAL: The sensor generates a magnetic field in the item, producing a reading. TECHNICAL: High-frequency magnetic fields induce resistivity calculations.
Conditions
- Item must be at room temperature
- Limitations based on size and thickness
- Models’ penetration depth varies, providing different insights
Advantages
- Easy to use and portable
- Non-destructive testing
- Capable of testing sealed items and penetrating more deeply than XRF
Disadvantages
- Requires knowledge of the item’s metal and alloy
- Cannot detect specific carat values or genuine items
- Specific gravity checks may be required for certainty
Cost: £1,000.00 to £2,500.00
Availability
Available at Trusti Metrix.
RESISTIVITY (metal detectors)
Overview
Used for detecting metals buried underground by ‘detectorists’.
Procedure
Sweep the ground and watch for signals.
How it works
Similar to testers for coins and bars, but in a ground-sweeping form.
Conditions
Choose a model specifically designed for gold detection, considering reach and potential depth.
Availability
Not available for purchase here.
Additional Information
Some metal detectors come with discrimination features to filter out unwanted metals, making the search for specific metals easier. It’s important to ground balance the detector to ensure accurate readings. Additionally, using headphones can help in hearing signals more clearly, especially in noisy environments.
ULTRASOUND
How they work: Ultrasound machines utilize sound-wave testing to determine homogeneity or filling levels, commonly used in engineering to inspect materials for flaws or inconsistencies.
Cost: The cost of ultrasound machines typically ranges from £750.00 to £1,000.00, depending on the brand and features.
Availability: Ultrasound machines are not available for sale in this location, but can be purchased online or through medical equipment suppliers.
MELT-AND-ASSAY (FIRE ASSAY)
How it works: Involves sampling, melting, refining, and assessing gold percentage.
Cost: From £50,000.00.
Heavy metal blood tests are conducted to determine the levels of harmful metals such as lead or mercury in the blood.
Metals can be naturally occurring, found in medications, supplements, and industrial products.
Prolonged exposure to excessive levels of metals can lead to damage to organs and neurological issues.
Testing typically involves samples of blood, urine, or hair and is also referred to as a toxic metals panel.
It is important to regularly monitor heavy metal levels in the body, especially for individuals who may be exposed to these metals through various sources.
Heavy metal toxicity can manifest in a variety of symptoms such as fatigue, headaches, digestive issues, and cognitive problems.
What is it used for?
Heavy metal tests assess metal exposure and concentrations in the body.
Why do I need a heavy metal blood test?
These tests are ordered when there is suspicion of metal exposure or symptoms of poisoning.
Symptoms can vary depending on the type of metal and the level of exposure.
Regular testing may be necessary for individuals working with metals, and children at risk of lead exposure should undergo testing, especially if living in older homes.
What happens during a heavy metal blood test?
A healthcare professional will draw a blood sample from a vein in your arm using a small needle. You may feel a slight sting upon insertion of the needle. The process usually takes less than five minutes.
After the blood sample is collected, it will be sent to a laboratory for analysis. The blood will be tested for the presence of heavy metals such as lead, mercury, arsenic, or cadmium. These metals can be toxic to the body in high levels and may cause symptoms such as fatigue, nausea, headaches, and neurological problems.
Results from the blood test can help healthcare providers determine if you have been exposed to high levels of heavy metals and guide treatment if necessary. If you have concerns about heavy metal exposure, speak to your healthcare provider about the possibility of having a blood test done.
Will I need to do anything to prepare for the test?
Avoid consuming seafood 48 hours before the test, as some fish and shellfish contain high levels of mercury.
Are there any risks to the test?
The risks associated with a blood test are minimal. You may experience minor pain or bruising at the site of the needle insertion, but these symptoms typically resolve quickly.
What do the results mean?
Elevated levels of a heavy metal in your blood may indicate heavy metal poisoning, although it is not always the case. Even in the absence of symptoms, reducing exposure to that metal may be necessary. Treatment might involve eliminating the heavy metal from the body, possibly through chelation therapy using oral medications or injections. Consider possible side effects before undergoing chelation therapy.
Normal or low levels of heavy metal in your blood usually suggest no heavy metal poisoning. However, some heavy metals can exit the bloodstream quickly and accumulate in tissues. Additional tests may be required if symptoms persist to check for heavy metals in other samples like urine, hair, skin, or fingernail clippings.
Accurate identification of metals is essential for projects involving metals. Different metals come in various grades and may be mixed with other elements to create alloys. Understanding the composition, manufacturing process, and mechanical properties of your metal is crucial for the successful completion of your project.
Common Metal Testing Methods
Various tests can assist in determining the alloy composition of metal. Basic tests like the surface appearance test provide insights into the metal’s characteristics. The spark test, involving grinding the metal to observe sparks, can also offer valuable information about the metal type.
Metal Identification Testing Order
Begin by determining whether the metal is magnetic or non-magnetic. Use identification trees to differentiate between the two types of metals. Further testing may be required for accurate metal identification.
Additional tests that can be used for metal identification include:
- Spark testing: observing the sparks produced when grinding the metal against a hard surface
- Chemical testing: applying different acids to the metal surface and observing the reactions
- Physical testing: measuring the density, hardness, and other physical properties of the metal
It’s important to follow a systematic approach when conducting metal identification tests to ensure accurate results. If in doubt, consult with a professional metallurgist or testing laboratory for assistance.
How do you determine steel grade?
Identifying steel grades can be complex due to the wide range available. Basic tests such as visually checking for an identification code or conducting a spark test can help narrow down the possibilities. Comparing the unknown steel with a known alloy can provide more precise results.
Learn more about steel grades
At Mead Metals, we supply high-quality metals to meet your project requirements. For detailed information on different steel grades, refer to our Steel Comparison Guide or visit our blog for insights on the main steel types. Contact us for expert guidance and quick quotes.