Use various filling materials (colored or colorless oil, artificial resin, wax, glass, etc.). ), under certain conditions (such as vacuum, pressure, heating, etc. ), directly fill the open cracks and holes in gems and the pores and grain gaps in jade, in order to cover up cracks or strengthen the structure.
1. Hot filling treatment
Sodium aluminosilicate or aluminosilicate glass is used to directly fill the opening cracks or holes of natural ruby raw materials or rings at high temperature (1400 ~ 1600℃) to fill the cracks, improve cleanliness and enhance durability. This kind of filled ruby is characterized by irregular and small secondary glass body, continuous distribution along the original section of the ruby, flat section and no melting erosion. This kind of secondary vitreous body exists in the form of single phase, with occasional bubbles. The secondary vitreous luster exposed on the surface of ruby crack is relatively weak (glass luster). Compared with ruby matrix (strong glass luster), the difference between them is very obvious, and it is easy to identify under ordinary ruby microscope (under the condition of top light) (see Figure 4-2- 1 1).
Figure 4-2- 1 1 filled ruby
Recently, a kind of filled ruby made of high lead glass has appeared in the jewelry market at home and abroad. This high lead glass material belongs to PbO-Al2O3-SiO2 system. It is characterized by low viscosity and softening temperature, good fluidity and strong permeability. After the filling treatment under the condition of medium temperature heating (600 ~ 680℃), the cracks or holes in the ruby can be well filled and healed, which can effectively improve the purity and transparency of the ruby.
Different from the traditional high-temperature filled rubies, this kind of filled rubies usually contains a small amount of crystal mineral inclusions such as acicular rutile and apatite with well-developed crystal forms. Because the refractive index of high lead glass (1.75) is close to ruby, the surface luster of glass filler is very close to ruby. Even under the gem microscope, the contact boundary between glass filler and ruby fracture surface is sometimes difficult to observe. Therefore, this kind of filled ruby is easily confused with untreated natural ruby in both appearance and internal characteristics. Under the microscope, most of the samples have a characteristic blue flash effect along the original crack (note that a few samples do not have this phenomenon), and there are bubble groups and gaps distributed in a plane along the original crack, leaving a local secondary glass body. X-ray spectrometer can be used to quickly detect the high concentration of lead.
2. Vacuum and pressure filling treatment
For some diamonds with low clarity (P grade) and developed open cracks, low-temperature high-lead glass is often used as filling material, which is directly filled under vacuum and medium-low temperature conditions, so that the cracks are well covered and the clarity is improved to a certain extent (the clarity may be improved by one or two grades). Due to the obvious yellow tone of high lead glass, the color grade of diamonds may be reduced after filling. Rotating this filled diamond under different illumination modes can present a characteristic abnormal flash effect along the primary fracture. That is, flashing purple and orange under dark light; In bright light, it will give off a blue-green flash. The durability of diamond caulking treatment is poor, and it will be destroyed by heating, acid or ultrasonic cleaning.
Emerald with early cracks is mainly filled with colorless oil, but its durability is poor. In recent years, artificial resin (opticon resin) has been widely used to fill cracked emeralds under vacuum, pressure and low temperature heating conditions, and the durability of emeralds after filling treatment has been significantly improved.
Using H3PO4/HNO3/H2O2 mixture as bleaching agent, Na OH as slagging agent, and epoxy resin as adhesive, under the conditions of continuous heating (about 120℃), vacuum and pressure, acid-base etching and filling treatment (commonly known as white slagging filling treatment) were carried out on jadeite flakes and green bodies. The surface and internal structure of jadeite jade pieces and blanks have changed obviously after being soaked in medium-strong acid and strong alkali for many times, forming a characteristic acid-base erosion particle structure. Then, the injected epoxy resin actually plays a dual role in strengthening solids and increasing transparency. After acid and alkali etching and heat curing, the purity and transparency of jadeite jade are significantly improved (commonly known as "B-grade jadeite jade"). It must be emphasized that the treatment of jadeite by acid-base etching and bleaching belong to two completely different basic concepts. The biggest difference between the two is that the internal structure and transparency of jadeite after acid and alkali etching have undergone "qualitative change", which is followed by the obvious bringing in and bringing out of the internal material components of jadeite (i.e. oxides or hydroxides of iron and manganese, polymer or organic wax), while the latter is the opposite (see Figure 4-2- 12).
Fig. 4-2- 12 filled jade
A kind of turquoise called "Paosong" has loose structure, large porosity and poor stability. The durability and color of this turquoise can be effectively improved by injecting artificial resin under vacuum and pressure and thermal curing.
(2) melt filling treatment
Based on cleavage and microcrack development in Myanmar Mong Hsu ruby, chemical fillers with weak fluxing properties such as sodium borate (borax) and polyphosphate are usually filled during heat treatment. At high temperature, the filled sodium borate and polyphosphate filler infiltrated along the original crack of ruby in fluid state and melted locally along both sides of the original crack surface, forming a multi-component mixed secondary melt. With the decrease of temperature, this mixed melt is separated and recrystallized, and some of it is recrystallized into regenerated ruby, but more of it is often too late to recrystallize, forming a bright and transparent secondary glass body, and finally the ruby cracks are repaired, filled and healed to varying degrees. The appearance characteristics of the secondary glass body distributed along the original section of the ruby are very similar to the flux plume and droplet contained in the ruby synthesized by flux method, which is sometimes difficult to distinguish.