Figure 1. Secondary-electron scanning electron microscope images showing morphologies of (A) natural and (B, D, and E) synthetic diamonds. C: Energy-dispersive X-ray spectrum for diamond in B. Natural diamonds are separates from felsic gneiss of Kokchetav massif, Kazakhstan. Synthetic diamonds are crystallized from graphite 1 Mg(OH)2 systems and exhibit irregular skeletal morphology similar to ...

widely encountered of the “fancy color” diamonds (figure 1). From 1998 to the present, GIA has issued grading reports on more than 100,000 yellow diamonds, by far the most common of the fancy-color diamonds submitted to our laboratory. In 2003, for example, 58% of the diamonds submitted for GIA Colored Diamond Grading Reports or Colored Diamond Identification and Origin of Color Reports were in...

This paper tests three hypotheses forthe origin of the tectosphere. Continental collision cannot explain the low metamorphic grade of crust that predates the tectosphere. Halfspace cooling and buoyant underplating can both fit the diamond age data, although underplating by buoyant subduction is the favored model. Thermal models provide a further test. If halfspace cooling formed the teetosphere...

It is widely assumed that mineral inclusions and their host diamonds are 'syngenetic' in origin, which means that they formed simultaneously and from the same chemical processes. Mineral inclusions that, instead, were formed earlier with respect to diamonds are termed protogenetic. However, minerals can have the same age as the diamonds in that they become enclosed in and isolated from any furt...

This paper investigates the relationship between the selling price of diamonds and their weight in carats. For this purpose, we use a unique sample of 112,080 certified diamonds collected from www.info-diamond.com during the first week of July 2011. We find substantial differences in pricing depending on cut shape. The price of diamonds increases markedly with the carat weight, with a price ela...

D iamonds are hard. Humans have known that for ages. This hardness encompasses not only mechanical hardness, but also chemical, electrical, optical, and structural hardness (1). Diamonds are hard to cut, and shaping them requires a complex technology. Diamonds are chemically inert and, because of this, they are not processed chemically. Diamonds are resistant to electrical fields and, as an ele...

The components of rock-forming and accessory minerals of the upper mantle, transition zone and lower mantle rocks have been involved into the processes of diamond genesis. Through their dissolving in primary carbonate melts, the mantle minerals have turned into components of the parental silicate-(±oxide)carbonate-carbon melts-solutions for diamonds and co-crystallized paragenetic minerals. The...