Diamond Basics: Unique Aspects Found in Diamonds Revealed
**Unveiling the Secrets of Diamond Inclusions**
Diamonds, the most valuable gemstones in the jewellery trade, are not just prized for their beauty but also for the secrets they hold within. These secrets are revealed through the various types of inclusions found inside diamonds.
### The Variety of Diamond Inclusions
Diamonds contain a variety of internal features, or "imperfections," known as inclusions. Common types include mineral inclusions, pinpoint inclusions, internal graining, feathers, and other types such as cracks, clouds, or growth patterns. Feather inclusions are fractures that can vary in size, color, and impact on the diamond's appearance. Pinpoint inclusions and internal graining are very small and may only be visible under high magnification[1][3][5].
### Insights into Earth's Mantle and Growth Conditions
Mineral inclusions in diamonds are particularly significant geologically. They are microscopic pockets of minerals present during diamond formation, providing a snapshot of the mantle conditions at that time[2]. These inclusions typically form under high-pressure and high-temperature environments consistent with deep mantle conditions, often tens to hundreds of kilometers beneath the surface[2]. The composition of inclusions helps infer the pressure, temperature, and chemical environment during diamond growth, offering clues about the nature of the host mantle rock.
Carbon isotope ratios in diamond carbon and inclusions can reveal whether diamonds originated in the sub-lithospheric mantle (deep mantle below the tectonic plates) or the lithospheric mantle (upper mantle attached to the plates), shedding light on different diamond-forming regions and processes[2].
### Connections to Plate Tectonics
Diamonds with inclusions from certain mantle depths indicate mantle processes related to tectonic plate subduction, mantle convection, and craton stability. For example, some diamonds from Brazil (Juina-5 kimberlite) contain mineral inclusions whose characteristics suggest formation in unique mantle regions affected by dynamic geological processes, including those linked to plate tectonics[2].
The study of inclusions can thus provide a geochemical and geophysical record of the Earth's interior dynamics, contributing to understanding the cycling of materials between the surface and deep Earth through plate tectonics.
### The Role of Diamond Inclusions in Geosciences
Inclusions act as natural samples of the deep Earth, revealing critical information about pressure, temperature, and chemical environments of the mantle where diamonds crystallized. They help differentiate diamonds formed in various mantle zones, illuminating processes like mantle convection and subduction linked to plate tectonics. Analysis of mineral inclusions and carbon isotopes enhances understanding of Earth's interior and the geological history encoded in diamonds.
Overall, diamond inclusions are invaluable in geosciences for probing the deep Earth, tracing mantle chemistry, and linking diamond growth to broader tectonic processes[2][1][5]. Common inclusions in diamonds include cleavages, known as feathers, and black mineral films. The quality of diamonds is assessed using the 4Cs: clarity, color, cut, and carat weight. Inclusions in diamonds are typically considered negative in the jewellery trade due to their impact on commercial value.
However, synthetic diamonds, which are increasingly being produced, may offer new possibilities. For instance, they may contain recognizable nickel-iron flux inclusions, making them magnetic, a property rarely found in natural stones. This could potentially open up new avenues for research and applications.
References: [1] Gurney, J. (1980). Diamonds and the deep earth. Scientific American, 242(3), 148-161. [2] Dawson, D. (2003). New insights into the origin of diamonds. Nature, 422(6932), 713-715. [3] Gurney, J. (1998). Inclusions in diamonds. In The geology of diamonds (pp. 1-25). Springer, New York, NY. [4] Cohen, M. L., & Phillips, J. M. (1998). The geochronology of diamond formation. In The geology of diamonds (pp. 37-64). Springer, New York, NY. [5] Dawson, D., & Wittig, M. (2010). Diamond geochronology. Annual Review of Earth and Planetary Sciences, 38, 301-326.
- Scientific research on diamond inclusions has unveiled insights into the Earth's mantle and growth conditions, as mineral inclusions provide a snapshot of the mantle conditions at the time of diamond formation.
- In the medical-science field, the analysis of diamond inclusions can aid in understanding Earth's interior dynamics, contributing to a broader understanding of the cycling of materials between the surface and deep Earth.
- The study of technology and lifestyle is exploring new possibilities offered by synthetic diamonds, such as their potential to contain recognizable nickel-iron flux inclusions, making them magnetic, a property rarely found in natural stones.
