How to Check Gold at Home: DIY Purity Tests You Can Try

If you are planning on buying or selling gold jewellery, it would be a good idea to understand how to check gold purity at home. After all, gold is not just a precious metal; it’s a major financial investment and a symbol of wealth. Nowadays, there are multiple cases of counterfeit and imitation pieces doing the rounds. Hence, verifying authenticity can save you from costly mistakes. Even though getting your gold professionally tested at certified jewellers is the most reliable method, there are also simple techniques that you can try at home.

Common Hallmarks to Identify Real Gold

Hallmarks are an essential step in confirming the authenticity of your gold. In India, the BIS (Bureau of Indian Standards) mark is the most widely trusted and accepted name, showing both purity and certification.

• Key Hallmarks:
   
  • BIS logo
  • Numeric purity indicator (e.g., 916 for 22K, 750 for 18K)
  • Assayer’s identification mark
     
• How to Read Hallmarks:
   
  • Look for purity number and logo together.
  • Ensure markings are clear and match official BIS records.
  • Cross-check jewellery certificates for verification.
     

Properly understanding hallmarks reduces the risk of buying counterfeit gold and ensures reliable valuation.

Understanding Gold Purity and Karat System

Gold purity is measured in karats (K), where 24K represents pure gold (99.9% purity). Lower karats like 22K, 18K, or 14K indicate that alloys such as copper or silver have been added to increase strength.

• Karat Numbers and Purity Percentages:
   
  • 24K: 99.9% pure
  • 22K: 91.6% pure
  • 18K: 75% pure
  • 14K: 58.3% pure
     
• Why Purity Matters:
   
  • Investors rely on purity for accurate valuation.
  • Gold purity affects eligibility and amount of gold loans.
  • Jewellery durability and resale value are linked to karat levels.

Testing Methods to Check Gold Purity at Home

While professional testing is always the most reliable, these simple at-home methods can help you identify whether your gold is real or fake.

1. The Float Test: A Simple Approach to Check Gold Purity

The float test is a straightforward method that utilises the density difference between gold and other metals. Using this method, you can test gold at home. To perform this test, fill a container with water and gently place the gold item you want to test into the water. Observe the behaviour of the gold:

If the gold sinks: This indicates that the item is likely genuine gold, as pure gold has a high density and will sink in water.

If the gold floats or hovers: This suggests that the item is not pure gold and may contain a significant proportion of lighter metals.

2. The Magnet Test: Assessing Gold's Magnetic Properties

Gold is non-magnetic, meaning it will not be attracted to a magnet. This property can be used to distinguish gold from base metals, which are often magnetic. Hold a strong magnet near the gold item you want to test. If the magnet attracts the item, it is likely not pure gold.

3. The Acid Test: A Cautionary Approach for High-Purity Gold

The acid test, also known as the nitric acid test, involves applying a drop of nitric acid to the gold item. This test is most effective for high-purity gold, typically 22 karats or higher. Observe the reaction:

If the acid turns green or blue: This indicates that the item is likely not pure gold and contains a significant amount of copper or other base metals.

If the acid leaves a reddish-brown mark: This is a sign of lower-purity gold, typically 18 karats or less.

If the acid leaves no mark: This suggests that the item is likely pure gold, as gold is resistant to nitric acid.

4. The Scratch Test (Ceramic Plate Test)

The scratch test is a quick and straightforward method to check the genuineness of your gold. For this method, you will need an unglazed ceramic plate. Simply rub the gold item gently against the surface of the plate and observe the streak it leaves:

• If the streak is gold-colored: This suggests the item is real gold.
• If the streak is black or gray: The item is likely fake or there is some impurity involved or made of another metal.

This test is simple and doesn’t require chemicals, but one has to be cautious. Scratching can slightly damage the surface of your jewellery. 

5. Visual Inspection: Looking for Hallmarks and Signs of Wear

6. Professional Grading: Seeking Expert Confirmation

If you have concerns about the authenticity of a valuable gold item, consider seeking professional grading from a reputable jeweller or appraiser. They have the expertise and tools to conduct more comprehensive tests and provide a definitive assessment of the gold's purity and value.

Checking gold at home can be a convenient and effective way to verify its authenticity and purity. While the methods discussed provide valuable insights, it is important to note that they are not fool proof. Professional grading remains the most reliable method for determining the true value and authenticity of gold, especially for high-value items.