Among natural gemstones, diamonds have an unshakable place in people's hearts and are a symbol of eternity.

But just how do people determine the age of a diamond?

Determining the age of a diamond is a complex process that involves analyzing various factors, such as geological formation, isotopic compositions, and impurities within the crystal lattice.

1. Geological Age

The first step in determining a diamond's age is to establish the geological age of the rock formation in which it was found. This involves studying the surrounding geological context and identifying the type of rock formation within which the diamond-bearing kimberlite or lamproite pipes are located.

2. Radiometric Dating

Radiometric dating is a powerful tool used to determine the age of rocks and minerals by measuring the ratio of parent isotopes to daughter isotopes. Radioactive elements, such as carbon-14, potassium-40, and rubidium-87, decay at known rates and can be used as dating markers. By analyzing the isotopic composition of minerals associated with diamonds, scientists can estimate their age.

a. Carbon-14 dating:

Carbon-14 dating is primarily used for organic materials younger than 50,000 years. As diamonds are formed from carbon-based minerals, this method can provide an estimate for diamonds found in younger geological deposits.

b. Potassium-argon dating:

Potassium-argon dating is often employed for dating older rocks, as it measures the decay of potassium-40 into argon-40. This method is useful for diamonds found in ancient geological settings.

3. Inclusion Geochronology

Inclusion geochronology is a technique that involves studying the mineral inclusions trapped within diamonds. By dating these inclusions, which are often minerals like garnet or zircon, scientists can infer the age of the diamond. The age of the inclusion provides a minimum age for the diamond, as the diamond itself must be younger than the inclusion.

4. Nitrogen Aggregation

Diamonds often contain nitrogen impurities present as isolated atoms or aggregated clusters. The aggregated nitrogen content can be a valuable indicator of a diamond's age. Over time, nitrogen aggregates increase in size due to the diffusion of additional nitrogen atoms. By measuring the size and density of these aggregated nitrogen centers, scientists can estimate the diamond's age.

5. Isotopic Signatures

Diamonds may contain isotopic signatures of volatile elements, such as carbon, nitrogen, and helium. These isotopic compositions can provide insights into the conditions and processes that led to their formation. By comparing these isotopic ratios with known geological and cosmic events, scientists can estimate the age of a diamond or determine its place of origin.

It is through this series of approaches that geologists can understand the age of each diamond and use it as a reference to determine their value.