Precious stones


The chemical formula is Be3Al2Si6O18 (aluminum bisilicate and beryl), belongs to the most precious variety of the beryl family. Considered by the era of the pharaohs as a symbol of hope, joy and chastity, according to Pliny, Cardano and many other authors, he comforts life and allows us to see “for a longer space”. It should be recalled in this regard that Nero used a concave emerald through which he observed the unfolding of the circus ludi. Emerald is a medium-high hardness stone (7.5-8 on the MOHS scale). The green color is due to small percentages of chromium, vanadium and iron. It can go from a pale pale green. Color, transparency (inclusions), brightness and quality of the cut are characteristics that determine the quality and therefore, a mass parity, the value of an emerald. An emerald completely devoid of inclusions is very difficult to find. The typical shape of the emerald is the octagonal cut, a step also called “emerald cut”, but it is also sought a form of oval, round, a heart and a cabochon. Important emerald fields are found in Colombia, but also in Brazil, Pakistan and Russia. Africa is also contributing with valuable emerald mines, which are located in Zambia, Zimbabwe and Madagascar.


It is the red variety of corundum, its chemical formula is Al2O3 (sesquiossido di alluminio) (aluminum sesquioxide) crystallized in the trigonal system. Together with the sapphire and after the diamond it is the hardest stone that exists in nature (9 of the MOHS scale). The red color is considered a small amount of oxide that is in place of aluminum part without disturbing the crystal structure. Ruby has always symbolized passion and spoke the language of love. It is a very rare stone and it is indeed difficult to find gems of good quality higher than two / three carats on the market. When a ruby ​​exceeds the six carats and is perfect it can be sold for any amount. The elements that influence the quality and therefore the value, with the same mass, are: color, transparency, brilliance and cut. The most common cuts are oval sheets, a pillow, octagon (or an emerald), or a cabochon cut, always oval or a cushion. Depending on the chosen cut, stones of the same weight can have very different returns. It is the cutter who decides which shape to take to the ruby ​​based on the type of raw material that has a function and in order to bring out the best possible color. Myanmar (formerly Burma) is the most famous source from which they come from Thailand (formerly Siam, with stones marked by the presence of traces of iron that have a color reminiscent of garnet), from Sri Lanka (ex Ceylon, from Kenya, from Tanzania and more recently from Vietnam (with stones that have a coloring reminiscent of those from Myanmar).


The blue-blue variety of corundum, its chemical formula Al2O3 (aluminum sesquioxide) and its color is given by the different proportions of titanium and iron. Together with the ruby, as hardness is second only to the diamond (9 scale MOHS). Considered by the ancients for its color an “air stone” and thus interpreted in the sky, it represents the symbol of divine justice, courage and trust in life. The blue sapphire can have colors ranging from light blue, even very clear, to a dark or very dark blue, even tending to black. Although the most sought after is the intense, velvety and bright blue. Come for the ruby, the elements that influence the quality and therefore the value, a mass parity, are color, transparency, brilliance and cut. They are more than ever an instrument, an oval, round, octagon or an emerald, or cut a cabochon (curved cut), shaped like a pillow and oval. This is how stones of the same weight can have different returns. It is the cutter who decides which shape to give to the sapphire based on the type of material that is a disposition, to the market request, to its own ability and in order to highlight the best possible color. Sapphires can come from mines located in Kashmir, in a beautiful cornflower color, generally of excellent quality but almost almost unobtainable. They also come from Myanmar (formerly Burma), from Sri Lanka (formerly Ceylon) of a color ranging from a pale celestial to blue, and from Thailand, Cambodia, Madagascar and Australia.


Its chemical formula is simply C, the name comes from the Greek adàmas which means indomitable, is the hardest stone known in nature (index 10 scale M0HS) and is carbon in its pure state, crystallized in the monometric system.
Ancient Sanskrit poems certify that it was known in the East as early as three thousand years before Christ, while in the West it was known only after the expeditions of Alexander the Great. Passed from antiquity to the present day, the faculty of the diamond to increase and make love lasting. Its rarity determines its value, just think that in the richest mines you need to work three tons of land to make a carat. The carat is the unit of measurement that determines the mass or weight of the gems and diamonds, in particular corresponds to 0.200 g.
The carats – together with color, purity and cut – are one of the four characteristics that combine to define rarity, quality and price of diamonds. .
Color – In order of rarity the colors that appear are: red, orange, blue, green and yellow, the intense colors are the so-called “fancies”. Although the most common color in world markets is “non-color”, that is white in its various shades or gradations. The classification of diamonds according to the Gemmological Institute of America, GIA (currently the only universally recognized), goes from D to Z.
D – exceptional white +
E – exceptional white
F – extra white +
G – extra white
H – white
I – white gradient +
J – shaded white
K – lightly colored white +
L – lightly colored white
M-N – colored white 1
O-P – colorful white 2
Q-R – white 3 color
S-Z – white 4 color
The classification of purity according to the GIA is as follows:
FL – free of inclusions
IF – internally free of inclusions
VVS 1 – very small inclusions difficult to detect at 10X
VVS 2 – very small inclusions difficult to detect at 10X
VS 1 – very small inclusions difficult to detect at 10X
VS 2 – very small inclusions difficult to detect at 10X
SI 1 – very small inclusions easily detectable at 10X
SI 2 – very small inclusions easily detectable at 10X
P 1 – inclusions visible to the naked eye
P 2 – inclusions strongly visible to the naked eye
P 3 – very strong inclusions visible to the naked eye
As far as cutting is concerned, the quality of the latter is essential to highlight the dispersion, fire and sparkle of the diamond. It depends on the ratio between the total diameter of the stone and other measures of the brilliant cut and its possible deviation from those that are the “ideal” ratios as shown in the diagram. The cut can therefore be classified as excellent, very good, good, mediocre and poor. Another feature that helps to identify the quality of a diamond is the fluorescence that can be defined as the emission of colored light from the inside of the stone in the presence of UV rays. It can be very strong, strong, medium or nothing.
For colors ranging from D to H the very strong or strong fluorescence can negatively affect the value of a diamond from 1% to 15% depending on the degree of purity. For colors ranging from I to N a strong or very strong medium fluorescence can positively influence the value of a stone in sizes ranging from 2% to 4%.
 This is because a fluorescent diamond may look better in daylight than in normalized white light or incandescent white light. As for the Fancy Color we are in the presence of the latter when in the diamond structure every 10,000 carbon atoms appears 1 atom of nitrogen. They can be classified in rarity order in Fancy Vivid, Fancy Intense, Fancy, Fancy Light. It is good to know that with the same cut and carving a Fancy Vivid or Fancy Intense diamond can have a higher or much higher value than a D / IF diamond.
Regarding the provenance, in the past the main sources of rough diamonds were India for more than 2,800 years and Brazil from the era of the conquistadores, while only since the end of the 19th century Africa has become the main source of world level. In particular, African diamonds currently come from South Africa, the Democratic Republic of the Congo, Botswana, Namibia, Angola, Sierra Leone, Liberia, Ivory Coast, Ghana, Central African Republic and Tanzania. Russia is also contributing to the extraction of rough diamonds along with Australia and Canada.
De Simone adheres to the Kimberly Process: diamonds offered for sale come or only from legitimate sources, not involved in conflicts, and in compliance with UN resolutions.