Small amounts of defects or impurities (about one per million of lattice atoms) color diamond blue (boron), yellow (nitrogen), brown (lattice defects), green (radiation exposure), purple, pink, orange or red.Diamond also has relatively high optical dispersion (ability to disperse light of different colors).Mobilization of permafrost carbon is expected to increase under future climate warming.
Based on incubation experiments, up to 10% of the Yedoma carbon is considered especially decomposable and may be released upon thaw.
The substantial amount of ground ice in Yedoma makes it highly vulnerable to disturbances such as thermokarst and thermo-erosion processes.
Special gemological techniques have been developed to distinguish natural diamonds, synthetic diamonds, and diamond simulants.
The word is from the ancient Greek ἀδάμας – adámas "unbreakable".
Permafrost is a distinct feature of the terrestrial Arctic and is vulnerable to climate warming.
Permafrost degrades in different ways, including deepening of a seasonally unfrozen surface and localized but rapid development of deep thaw features.
In the 20th century, experts in gemology developed methods of grading diamonds and other gemstones based on the characteristics most important to their value as a gem.
Four characteristics, known informally as the four Cs, are now commonly used as the basic descriptors of diamonds: these are carat (its weight), cut (quality of the cut is graded according to proportions, symmetry and polish), color (how close to white or colorless; for fancy diamonds how intense is its hue), and clarity (how free is it from inclusions). The formation of natural diamond requires very specific conditions—exposure of carbon-bearing materials to high pressure, ranging approximately between 45 and 60 kilobars (4.5 and 6 GPa), but at a comparatively low temperature range between approximately 900 and 1,300 °C (1,650 and 2,370 °F).
The deposits formed due to a combination of aeolian, colluvial, nival, and alluvial deposition and simultaneous ground ice accumulation.