The heating temperature of rubies and sapphires is about 1300- 1900℃, and the inclusions in rubies and sapphires will change to some extent. For example, when sapphires are heated, their colors will change. For example, light-colored sapphires will be heated to blue, and light yellow or yellow-green sapphires will be treated to orange or even golden sapphires when heated under oxidizing conditions.

2. Needle-like inclusions will dissolve continuously with the increase of temperature, and finally break into discontinuous short filaments or become tiny shapes like dust spots.

3. For example, the solid crystal inclusions contained in rubies and sapphires will be dissolved in different degrees, and the crystal edges will be rounded and become snowball-shaped inclusions, or "disc-shaped" stress cracks will appear around the crystals.

4. In some gas-liquid inclusions, under the condition of high temperature and high pressure for a long time, the gas or liquid inside the inclusions will burst and the liquid will flow into the newly cracked cracks. This crack also looks like a stress crack, but from a certain angle, you will see the interference color.

5. Under the ultraviolet fluorescent lamp, natural rubies show weak-moderate red fluorescence, while rubies show blue-white fluorescence after heating, while natural sapphires are inert and do not emit light, and some blue sapphires show light green or light blue fluorescence after heating.

Second, the surface diffusion treatment

1. Ruby uses high temperature to let Cr ions enter the surface lattice of light red corundum, forming a thin red diffusion layer on the surface.

When the sample is put into diiodomethane, the color of the dispersed ruby is mostly concentrated in the waist edge, faceted edge and open crack. In contrast, diffused rubies seem to have boundaries, while natural rubies have blurred boundaries.

2. Sapphire often uses high temperature to make Fe and Ti as chromogenic agents to produce a blue diffusion layer on the surface of colorless or light-colored sapphire. The principle is the same as the diffusion of ruby. Different color developers can make sapphire diffuse into different colors.

In addition to putting sapphire in diiodomethane to observe whether it diffuses, you can also observe it with a magnifying glass. Put a tissue on the lamp at the bottom. The sapphire sample has the mesa facing down, and the diffused color is concentrated along the edge of the facet or the opening crack, which looks like a spider web structure.

3. The star ruby diffused on the surface, and the star line is similar to synthetic. The natural star line looks like it comes from the inside of the stone, and there seems to be a treasure light in the center where the three star lines intersect. The natural star line is thick in the middle and thin at both ends, so it can be discontinuous, while the synthetic star line looks like floating on the surface of a gem. The synthetic star line is straight, uniform, good in continuity and without treasure in the center.

Three. Bulk diffusion (beryllium diffusion)

This kind of diffusion also uses high-temperature oxidation to diffuse Be into the gem, but unlike surface diffusion, surface diffusion is only in a thin layer on the surface, but deeper inside the gem. This diffusion is mainly to treat colorless or nearly colorless sapphire into yellow or orange. The treated sapphire is very similar to Padma sapphire, which is a lotus sapphire with a pink-orange tone.

This kind of gem identification can be put in diiodomethane, the color of the outer ring layer is orange, the color of the inner ring layer is pink, and occasionally it is colorless. Or go to an appraisal institution and measure the ion concentration with a large instrument. Be concentration near the surface is relatively high, and gradually decreases towards the center.

Fourth, glass filling.

Everyone knows that ruby has "ten Hong Jiu cracks". In order to make the ruby look less cracked, the filler will be pressed into the cracks of the ruby with molten lead glass, so that the ruby looks less cracked.

Because the refractive index of ruby is 1.76- 1.78, and the refractive index of lead glass is 1.45- 1.70, the gloss will be different, resulting in different gloss. Generally, gemstones will be filled with glass when there are many cracks, so the whole looks foggy and unnatural.

Observing with a magnifying glass, we can see bubbles, agitated vortex structure and abnormal blue flash during filling. Reflecting light, you can see the filler in the open crack.

Verb (verb's abbreviation) The fusion of cracks in natural products.

In the heat treatment, it is necessary to add a heat conductive agent-sodium borate to prevent the crack from bursting. But after melting, the heat-conducting agent will enter the open cracks, and with the decrease of temperature, these heat-conducting agents will solidify in the cracks.

Generally speaking, sodium borate is visible at the magnification of 10x, which is called filling, while the invisible one is called heat treatment.

Six, radiotherapy

General sapphire treatment, colorless sapphire is radiated into yellow, pink sapphire is radiated into orange, blue sapphire is radiated into green and so on.

Seven, dyeing treatment

The cracked rubies and sapphires are soaked in organic dyes, heated and then colored.

1. This gem can be wiped with a cotton ball dipped in alcohol or acetone, and then dyed.

2. Magnified observation shows that the pigment is concentrated around the crack.

3. Dyed gems may have special fluorescence, which is the fluorescence of pigments.

The above are the common optimization methods of rubies and sapphires on the market at present. Friends who are interested in rubies and sapphires or are ready to start, must keep their eyes open and see if the stones they buy have been optimized or processed before they are worth the money. Don't be fooled by some unscrupulous merchants, prepare the necessary theoretical knowledge and let them know that they are experts, so that they dare not shoddy. If you have any questions, or welcome to ask questions and give guidance, we will study together and make progress together.