Which Verification Methods Ensure Gold Dust Purity in Field Testing?
Timp:
17 November 2025
Ensuring the purity of gold dust in field testing requires methods that are practical, efficient, and accessible in non-laboratory conditions. Here are several verification methods commonly used in the field to test gold dust purity:
1. Inspecție vizuală
- Gold has a distinct yellow sheen that doesn’t dull or tarnish easily.
- Analysts inspect the dust for uniformity in color and assess whether it looks like pure gold or if impurities (dirt, other metals) are noticeable.
2. Magnet Test
- Gold is non-magnetic. Using a strong magnet can confirm if the gold dust contains ferrous impurities like iron or nickel.
3. Density Test
- Gold is exceptionally dense, with a specific gravity of approximately 19.3. Field testers often compare the gold dust’s weight and volume to estimate its density.
- A crude method involves observing how the dust behaves in water (gold sinks rapidly due to its density).
4. Acid Test (Nitric Acid)
- Nitric acid is used to determine if the material contains impurities or is alloyed with other metals.
- Pure gold does not react with nitric acid, whereas less pure samples or alloys may fizz, discolor, or dissolve partially when exposed to the acid.
5. Touchstone Method
- A small amount of gold dust is rubbed onto a touchstone to create a streak. The streak’s color is then compared to gold alloys of known purity using acid solutions to estimate its karat value.
6. Electronic Gold Tester
- Handheld electronic testing devices can analyze the electrical conductivity and provide a quick reading of gold purity. These devices are portable and commonly used in the field.
7. XRF Analyzer (Portable)
- Portable X-Ray Fluorescence (XRF) analyzers can non-destructively test metals for their elemental composition, including gold purity.
- While expensive, they are highly reliable and becoming more accessible for field applications.
8. Panning
- A traditional method relies on separating gold dust from lighter materials by placing it in a pan and swirling it in water.
- Pure gold particles settle at the bottom due to their high density.
9. Fire Assay (Portable Kits)
- Portable fire assay kits involve melting the sample to separate gold from impurities and determine its purity.
- While not highly practical for every field setting, small-scale kits may be used.
10. Comparison with Known Samples
- Field testers may bring reference samples of pure gold to visually or physically compare density, color, and other physical properties.
Note:
Field testing is generally less precise than laboratory-grade equipment but can provide reasonably accurate insights when more sophisticated methods are unavailable. It’s often followed by more detailed analysis to confirm results.
Contact Us
Shanghai Zenith Mineral Co., Ltd. is a leading manufacturer of crushing and grinding equipment in China. With more than 30 years of experience in the mining machinery industry, Zenith has built a strong reputation for delivering high-quality crushers, mills, sand-making machines, and mineral processing equipment to customers around the world.
Headquartered in Shanghai, China, Zenith integrates research, production, sales, and service, providing complete solutions for aggregates, mining, and mineral grinding industries. Its equipment is widely used in metallurgy, construction, chemical engineering, and environmental protection.
Committed to innovation and customer satisfaction, Shanghai Zenith continues to advance in intelligent manufacturing and green production, offering reliable equipment and comprehensive after-sales service to help clients achieve efficient and sustainable operations.
website: https://www.chinagrindingmill.net
E-mail:info@chinagrindingmill.net
Whatsapp:+8613661969651
