Formica was the first in the world to develop a completely new material, imitating gemstones - glass-ceramic (protected by US Patent No.: 9,801,435 B2). From the huge variety of existing types of glass-ceramics, we managed to choose a composition that allows us to obtain a new material with such optical, mechanical, and other physical properties that are as close as possible to the most popular natural gems - emerald, topaz, tourmaline, spinel, garnet, and many others.
Cordierite glass-ceramic of the SiO2-Al2O3-MgO system was chosen as the most optimal composition.
This new material was registered under the trade name SIAMITE (Reg. No. 5,531,572 in US Patent and Trademark Office). There were two reasons for this: 1) chemical composition of the main components SiO2, Al2O3, MgO – (SiAM), 2) production was set up in Thailand historically known as SIAM. In addition to the main components mentioned above, the material contains small amounts of alkali as well as some coloring, fining and nucleating agents.
However, before the official registration of SIAMITE, it was named: nanocrystal and nanogem. These names are now very common and come from the nanosized (about 10⁻⁷cm) crystals grown inside an amorphous substance.
The presence of nanocrystals of spinel (gahnite), rutile, zirconium titanate and others in SIAMITE is proven by X-ray diffraction analysis. Variations of physical properties, changes in the absorption spectrum, higher density, transformations in the refractive index and enhanced mechanical properties. Special studies revealed that glass-ceramics typically have a 20%-30% increase in hardness when compared to the original glass
SIAMITE is a nanocrystalline glass-ceramic material, comprising nanosized crystals of spinel and other minerals (depending on color) uniformly distributed in the amorphous high temperature aluminosilicate glass matrix. The size and concentration of nanocrystals affect the degree of transparency of the material and its color. As they increase, the transparent material becomes first translucent and then opaque.
According to transparency, SIAMITE, produced by Formica, is divided into 3 groups: Transparent, Translucent and Opaque. In transparent SIAMITE®, the characteristic sizes of nanocrystals - spinel, rutile, zirconium titanate and other minerals do not exceed 10 nanometers (5-10 nm). In translucent varieties (opals or opalites) they increase up to 25 nm, and in opaque varieties they exceed 25-30 nm. Accordingly, the total volume of nanocrystals grows relative to the residual amorphous mass (glass).
The Transparent SIAMITE® catalog consists of 108 color groups, and each of them contains a spectrum of colors from very dark to very light - a total of abou 750 colors. They completely replicate the brightness, color, and density of the most widely used gemstones: Topaz (London Blue, Swiss, Sky, Brown, and Tea color), Tourmaline (Pink, Rose, Red, Green), Garnet (Demantoid, Tsavorite, Spessartine, Rhodolite, Pyrope, Almandine),Spinel (Blue, Gray, Pink, Red),Aquamarine, Emerald, Sapphire, Ruby, Paraiba, Tanzanite, Kunzite, Amethyst, Citrine, and others. (Fig. 4). This is due to their physical properties - hardness of 7-7.5, density 3-3.3 g/cm3, refractive index RI = 1.61-1.63 - very close to the natural gems mentioned above.
The ability to produce many colors, shades and saturations is another unique feature of SIAMITE. This allows to produce a wide range of imitations of natural gems from different deposits: emeralds from yellowish green to bluish green (Zambian, Brazilian, Colombian, and other types); sapphires from gray blue to violet blue (Australian, Ceylon, ...); amethysts from violet to purple blue and purple (Brazilian, Uruguayan, ...), topaz (London Blue, Swiss Blue, Sky Blue) and so on. And the abundance of choice in saturation allows you to have cut stones of any shape with the same color in the range from 0.8 mm to 20 mm at least
Most importantly - all these transparent gemstones reflections, regardless of shape and size, are resistant to thermal shocks
The uniqueness of the properties of glass-ceramics allows you to get an unlimited range of varieties not only in color but in transparency as well. This is achieved by controlling changes in the nanocrystal`s concentration and particle size. Now, the Translucent and Opaque SIAMITE catalog is limited to only 200 varieties but can be greatly expanded if necessary. They imitate such decorative gemstones as moonstone, cacholong, chrysoprase, jade, lapis lazuli, turquoise, black spinel, and others.
It is important to consider that the degree of transparency is determined not only by the size and concentration of nanocrystals of spinel and other minerals, but also by the thickness of the cabochon or cut stone. That is, a stone that is translucent, for example, in 5mm will be almost opaque at 8-10 mm. Accordingly, as the transparency of the stone decreases, its color gradually changes. The hardness, density and resistance to thermal shock are approximately the same as those of transparent SIAMITE.
SIAMITE is a green technology gemstone
Siamite is lead free and in compliance with the strictest regulatory industry norms and laws regarding the restriction or prohibition of certain substances. The production process is virtually waste-free and does not damage the environment - as in any glass production, all low-quality or defective products return to production as additives to the charge. The source of energy is only electricity. Therefore, the production of glass-ceramics is not accompanied by the carbon dioxide emissions into the atmosphere.
Reserves of natural gems are depleted, value has increased, and their mining causes irreparable damage to nature. Nowadays, consumers increasingly realize and become eager to save nature, giving precedence to environmentally friendly products. Recently, a very well-known jewelry brand refused to use natural diamonds and replaced them with lab-grown ones. Colorless SIAMITE cannot compete with lab-grown diamonds, moissanite, or even cubic zirconia due to its relatively low refractive index. However, colored SIAMITE are ideally capable of imitating most colored gemstones and therefore allows us to take care of nature and not disfigure it with quarries, trenches, and mines.
Lab-created SIAMITE glass-ceramic delivers unusual property combinations, such as an extremely low thermal expansion coefficient, optical transparency or translucency, high hardness, fracture strength and toughness, and chemical durability. Thus, available in an extensive assortment of colors, shapes, and sizes, affordable to the masses, SIAMITE opens a multitude of creative design possibilities through numerous application techniques, making it ideal for use in the jewelry and accessories industries.