Diamond
A variety of Minerals
What is Diamond?
Diamonds are incredible minerals that are composed solely of humble carbon. First mined in India as far back as 400 BC, they have only become popular during the last few centuries. Cut stones are prized for their brilliance, their dispersion (also known as "fire" - or the ability to convert white light into many different colors of light), and their hardness. Indeed, their extreme durability makes even specimens that are below gem-quality extremely useful in all manner of industrial, commercial, and medical settings, particularly when cutting or grinding is involved.
Uses & Applications
Diamond is an extremely popular gemstone. However, because it is the hardest known naturally occurring mineral, it is commonly used to make extremely tough drills and blades used to penetrate other hard materials. Many dentists use diamond-tipped drills to treat cavities and polish teeth.
Healing Properties
Diamond is believed to be one of the most powerful of stones. Said to offer access to Divine energy, the stone is often used to attract love, respect, and emotional growth while cleansing the aura from negativity. It is often worn on the Third Eye chakra to improve mental clarity and provide healing energy to the physical body.
Optical Properties
- Refractive Index
- 2.417-2.419
- Pleochroism
- None
- Optical Character
- Isotropic
- Dispersion
- 0.044
Discover Values
This stone excels in popularity, beauty, collection value.
Diamond Market Value Calculator
Estimate the market value of Diamond using size, quality, and finish. This preview calculator is for quick context and is not a formal appraisal.
Diamond Localities Map
See where Diamond is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
The Meaning
The diamond was thought to represent the sun in Ancient Egypt, whilst Hindus in Ancient India believed that they could attract lightning. Ancient Greeks and Romans thought diamonds were the tears of gods. Diamonds also symbolize faithfulness and commitment between two people in a relationship, which is why, in some cultures, a diamond ring is a symbol of engagement or intention to marry.
Geochemistry
Diamonds are extremely rare, with concentrations of at most parts per billion in source rock. Before the 20th century, most diamonds were found in alluvial deposits. Loose diamonds are also found along existing and ancient shorelines, where they tend to accumulate because of their size and density. Rarely, they have been found in glacial till (notably in Wisconsin and Indiana), but these deposits are not of commercial quality. These types of deposit were derived from localized igneous intrusions through weathering and transport by wind or water. Most diamonds come from the Earth's mantle, and most of this section discusses those diamonds. However, there are other sources. Some blocks of the crust, or terranes, have been buried deep enough as the crust thickened so they experienced ultra-high-pressure metamorphism. These have evenly distributed microdiamonds that show no sign of transport by magma. In addition, when meteorites strike the ground, the shock wave can produce high enough temperatures and pressures for microdiamonds and nanodiamonds to form. Impact-type microdiamonds can be used as an indicator of ancient impact craters. Popigai crater in Russia may have the world's largest diamond deposit, estimated at trillions of carats, and formed by an asteroid impact. A common misconception is that diamonds are formed from highly compressed coal. Coal is formed from buried prehistoric plants, and most diamonds that have been dated are far older than the first land plants. It is possible that diamonds can form from coal in subduction zones, but diamonds formed in this way are rare, and the carbon source is more likely carbonate rocks and organic carbon in sediments, rather than coal.
Associated Chakras
Key Characteristics
Characteristics of Diamond
Diamond is a solid form of pure carbon with its atoms arranged in a crystal. Solid carbon comes in different forms known as allotropes depending on the type of chemical bond. The two most common allotropes of pure carbon are diamond and graphite. In graphite the bonds are sp orbital hybrids and the atoms form in planes with each bound to three nearest neighbors 120 degrees apart. In diamond they are sp and the atoms form tetrahedra with each bound to four nearest neighbors. Tetrahedra are rigid, the bonds are strong, and of all known substances diamond has the greatest number of atoms per unit volume, which is why it is both the hardest and the least compressible. It also has a high density, ranging from 3150 to 3530 kilograms per cubic metre (over three times the density of water) in natural diamonds and 3520 kg/m in pure diamond. In graphite, the bonds between nearest neighbors are even stronger but the bonds between planes are weak, so the planes can easily slip past each other. Thus, graphite is much softer than diamond. However, the stronger bonds make graphite less flammable. Diamonds have been adapted for many uses because of the material's exceptional physical characteristics. Of all known substances, it is the hardest and least compressible. It has the highest thermal conductivity and the highest sound velocity. It has low adhesion and friction, and its coefficient of thermal expansion is extremely low. Its optical transparency extends from the far infrared to the deep ultraviolet and it has high optical dispersion. It also has high electrical resistance. It is chemically inert, not reacting with most corrosive substances, and has excellent biological compatibility.
Formation of Diamond
Diamonds in the mantle form through a metasomatic process where a C-O-H-N-S fluid or melt dissolves minerals in a rock and replaces them with new minerals. (The vague term C-O-H-N-S is commonly used because the exact composition is not known.) Diamonds form from this fluid either by reduction of oxidized carbon (e.g., CO2 or CO3) or oxidation of a reduced phase such as methane. Using probes such as polarized light, photoluminescence and cathodoluminescence, a series of growth zones can be identified in diamonds. The characteristic pattern in diamonds from the lithosphere involves a nearly concentric series of zones with very thin oscillations in luminescence and alternating episodes where the carbon is resorbed by the fluid and then grown again. Diamonds from below the lithosphere have a more irregular, almost polycrystalline texture, reflecting the higher temperatures and pressures as well as the transport of the diamonds by convection.
Composition of Diamond
The most common crystal structure of diamond is called diamond cubic. It is formed of unit cells (see the figure) stacked together. Although there are 18 atoms in the figure, each corner atom is shared by eight unit cells and each atom in the center of a face is shared by two, so there are a total of eight atoms per unit cell. Each side of the unit cell is 3.57 angstroms in length. A diamond cubic lattice can be thought of as two interpenetrating face-centered cubic lattices with one displaced by 1/4 of the diagonal along a cubic cell, or as one lattice with two atoms associated with each lattice point. Viewed from a <1 1 1> crystallographic direction, it is formed of layers stacked in a repeating ABCABC ... pattern. Diamonds can also form an ABAB ... structure, which is known as hexagonal diamond or lonsdaleite, but this is far less common and is formed under different conditions from cubic carbon.
Health & Safety Information
- ⚠️The forecasted mass of diamond clay tailings (saponite) to be discharged after ore processing makes up millions of tons. Worryingly, when macro- and micro-components are found in non-hazardous concentrations, fewer efforts are put into the environmental management of the tailings, though technogenic sediments offer prospects for reuse and valorization beyond their traditional disposal. Saponite is a demonstrative example of the tailings constituent that is often left unfairly mistreated. Reducing the impact of the tailings can be achieved through the reuse of the stored clay magnesia rocks obtained from saponite-containing suspension. Electrochemical separation helps to obtain modified saponite-containing products with high smectite-group minerals concentrations, lower mineral particles size, more compact structure, and greater surface area. These characteristics open possibilities for the manufacture of high-quality ceramics and heavy-metal sorbents from saponite-containing products. Furthermore, tail grinding occurs during the preparation of the raw material for ceramics; this waste reprocessing is of high importance for the use of clay pulp as a neutralizing agent, as fine particles are required for the reaction. Experiments on the Histosol deacidification with the alkaline clay slurry demonstrated that neutralization with the average pH level of 7.1 is reached at 30% of the pulp added and an experimental site with perennial grasses proved the efficacy of the technique. Moreover, the reclamation of disturbed lands is an integral part of the social and environmental responsibility of the mining company and this scenario addresses the community necessities at both local and regional levels.
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Quick Facts
Physical Properties
- Color
- Colourless, yellowish to yellow, brown, black, blue, green or red, pink, champagne-tan, cognac-brown, lilac very rare
- Hardness (Mohs)
- 10
- Density
- 3.515 g/cm³
- Streak
- none
- Luster
- Adamantine, Greasy
- Crystal System
- Isometric
Chemical Properties
- Chemical Formula
- C
- Elements
- C
Also Known As
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