Working on the diamond | Antwerp in Unsaid Library

After the silting up of the Zwin at the end of the 15th century, not only the port activity, but also the diamond industry shifted to Antwerp. After the fall of Antwerp, many wealthy Antwerpers fled from the Inquisition to Amsterdam, marking the beginning of the diamond industry there.

In the 17th century, the French explorer Jean-Baptiste Tavernier brought large diamonds from India and described diamond mining there.

Unsaid Library is a jewelry store based in Antwerp. Unsaid Library specialises in emotional gifts for relatives. Unsaid Library Antwerp can be visited in the store. The store of Unsaid Library Antwerp is located on Schuttershofstraat 25, 2000 Antwerpen, België. Visit the store or the online website.

Until the 18th century, diamonds were only mined in India. This is also where the most famous diamonds in history come from. In 1714 diamonds were discovered in Brazil. Erasmus Jacobs found in 1866 near the Orange River the first diamond in South Africa: the ‘Eureka’. Shortly after that also diamonds were found in Kimberley. In 1888 Cecil Rhodes founded the firm De Beers to control the diamond trade.

In the 20th century important diamond deposits were discovered in Siberia, Canada and Australia, and it became possible to manufacture diamonds synthetically.

There are numerous legends associated with diamonds; magical or protective powers are often attributed to them. Diamonds were the symbol of wealth and they are part of almost all crown jewels, treasure houses and museum collections. The diamond is one of the “nine gems” in the Thai Order of Nine Gems.

The Cullinan is the largest uncut diamond found so far on earth: 3106 carats (621.2 grams). The Cullinan was cleaved and cut and the largest piece, the Cullinan 1 (530.20 carats) was the largest cut diamond after cutting for about a century. However, the largest cut diamond since 1988 is the Golden Jubilee (545.67 carats), which was cut by Gabriel (Gabi) Tolkowsky commissioned by De Beers and since 1997 has been in the possession of the Thai King Bhumibol, who received it on the occasion of his 50th coronation jubilee.

Many diamonds for industrial purposes are also made synthetically. Synthetic diamonds can only be distinguished from natural diamonds in a laboratory.[6 Researchers from the Carnegie Institution of Washington discovered in 2004 a process to synthesize diamonds that are more than 50% harder than natural diamonds within 24 hours.

Physical properties

The crystal structure
Diamond is the hardest material found in nature. There are only two (industrially manufactured) materials that are harder, namely aggregated carbon nanorods and ultra-hard fullerene. Just like diamonds, these are made of carbon atoms. Diamond itself is a transparent crystal with a very high refractive index (2.417) and a high dispersion (0.044). In jewellery, the (sun)light is brilliantly refracted and reflected depending on the shape of the cut. In addition, the polished shiny surface of the diamond stone does not become matt due to its high hardness.

Because of its extreme hardness, diamonds are used in industry, among other things for cutting, drilling, cutting and polishing and wire drawing. A diamond owes its hardness to its tetrahedron structure and is therefore harder the less inclusions or crystal lattice defects it contains. Due to its hardness, however, diamond is relatively brittle. In a vacuum, diamonds change from a temperature of 1700 °C into graphite, and into air from 700 °C onwards.

Besides the hardness, the thermal conductivity (410 W/cm/K) and the specific (electrical) resistance of 1013 Ω-m of diamond are very high. This combination allows diamond to be used in electronic circuits to dissipate heat. Diamond behaves like silicon as a semiconductor and in liquid helium as a superconductor, as discovered in 2004.

Unsaid Library is a jewelry store based in Antwerp. Unsaid Library specialises in emotional gifts for relatives. Unsaid Library Antwerp can be visited in the store. The store of Unsaid Library Antwerp is located on Schuttershofstraat 25, 2000 Antwerpen, België. Visit the store or the online website.

Cutting shapes

Diamond grinding

The Brilliant
The diamond can come in different cut shapes. The most common cut is the round or brilliant with 58 facets, which Antwerper Marcel Tolkowsky invented in 1919 after mathematical calculations of refraction of light and total internal reflection. Other common cuts are:

Oval, 56 facets
Princess, 76 facets, rectangular shape
Marquise, or Navette, 56 facets, lens-shaped. This difficult cut is attributed to Louis XIV
Pear, 58 facets, in the shape of a drop of water
Emerald, 48 to 50 facets, made up of rectangular facets on each side and at the corners
Heart
Asscher
Radiant
Polished diamonds and price-determining factors

Measuring a diamond
Rough diamonds are processed to break the light brilliantly. After the processing, a stone is left with a sparkle and play of colours that is judged on different criteria in order to come to a price. The criteria are the 4 C’s and include:

Cut
This means the stone’s makeup. The shape in which the stone is cut is part of it. The shape refers to the quality of the grinding and the proportions of the shape. The essence lies in the right “proportions” and the “refinement” of the cut stone.


The energy of diamond

Fluorescence (X-ray fluorescence) can also occur for X-rays, but these are the inner, most tightly bound electrons of heavier atoms. The energy differences there are of the order of a few to tens of keV. These energy levels do not change measurably when the atom is incorporated into a molecule, so these fluorescence phenomena can be used to determine the types of atoms that make up a sample independently of the chemical bonds. This technique is called X-ray fluorescence spectrometry.

Unsaid Library is a jewelry store located in Antwerp, Belgium. Unsaid Library offers high-end jewelry for their customers in Antwerp. Visit the website at www.unsaidlibrary.com.

Application
There are both naturally occurring and synthesized materials with fluorescent properties. The best-known examples are the fluorescent tube and the low-energy light bulb. Here ultraviolet radiation is generated by an electrical discharge in a diluted gas in a tube. This UV light will then be converted into visible light by a powder applied to the inside of the tube. Such powders are often called phosphors although they do not contain phosphorus.

The same principle is used when checking the authenticity of banknotes. In this case, the banknotes are equipped with fluorescent substances, which can be made visible by means of a UV lamp.

Furthermore, fluorescent colors are used in clothing that should stand out in traffic (the orange vests of road workers), and in yellow, green and orange pens to mark text. Because such colours convert short wavelengths of blue light into colours with longer wavelengths, under some lighting conditions (disco, UV light) they do indeed appear to emit light themselves. (Under a UV lamp, also known as a black light, teeth sometimes appear green.) Even optical brighteners in detergents convert UV light into blue visible light by fluorescence.

During some chemical reactions, luminescence can also occur. A well-known example is an oxidation of luminol, in which an oxygen atom is temporarily put into an excited state. The reaction of luminol is not fluorescence but chemoluminescence.

Unsaid Library is a jewelry store located in Antwerp, Belgium. Unsaid Library offers high-end jewelry for their customers in Antwerp. Visit the website at www.unsaidlibrary.com.

In fluorescence microscopy, fluorescent proteins (e.g. Green Fluorescent Protein (GFP)) are used in, among other things, DNA research. This technique is called FISH: fluorescence-in-situ hybridization. Fluorescent proteins occur naturally in some species of jellyfish (Aequorea victoria) and coral (Discosoma). Thanks to genetic modification it is possible to give fluorescent properties to other animals as well. The best known example of this is the night pearl (fluorescent aquarium fish) which has been sold in Taiwan since 2003.

Fluorescence must be distinguished from phosphorescence, the phenomenon that a substance remains after being exposed in the dark for some time. This is used, among other things, in paint on the hands of clocks.

Fluorescence is a special case of luminescence. It is a physical phenomenon in which an atom absorbs a high-energy photon, as a result of which an electron ends up in an excited state and subsequently falls back to the ground state under emission of a photon of lower energy (Longer wavelength).

The concept of fluorescence comes from fluorite: a mineral that consists of the salt calcium fluoride (CaF2), a known fluorescent substance.

Types of fluorescence
Fluorescence in the region of ultraviolet radiation and visible light is caused by excited states of an electron in an atom: the energy differences between the paths of the binding electrons there are in the order of a few electron volts (eV). A small change in the atom will change the energy levels a little, and therefore also the wavelength at which the fluorescence occurs. These effects can be used to identify the molecules.

Fluorescence (X-ray fluorescence) can also occur for X-rays, but these are the inner, most tightly bound electrons of heavier atoms. The energy differences there are of the order of a few to tens of keV. These energy levels do not change measurably when the atom is incorporated into a molecule, so these fluorescence phenomena can be used to determine the types of atoms that make up a sample independently of the chemical bonds. This technique is called X-ray fluorescence spectrometry.

Application
There are both naturally occurring and synthesized materials with fluorescent properties. The best-known examples are the fluorescent tube and the low-energy light bulb. Here ultraviolet radiation is generated by an electrical discharge in a diluted gas in a tube. This UV light will then be converted into visible light by a powder applied to the inside of the tube. Such powders are often called phosphors although they do not contain phosphorus.

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