Zhang Jinfu

Yunnan Provincial Gem and Jade Professional Committee Kunming, Yunnan 650041

Preface

The research on jade has made great progress in recent years, with many new understandings in its mineral composition, structural structure, color formation mechanism and classification; new breakthroughs have also been made in the evaluation of quality and commercial. Many experts and scholars in the geological industry in Yunnan have made outstanding contributions to jade research, achieved fruitful results, and had a huge impact on the development of the jewelry industry at home and abroad. Over the past decade, I have accumulated some knowledge in researching and learning jade with my colleagues, but I have made a lot of complex and mysterious achievements.

Because I dare not say any specific opinions. During my field inspection with the inspection team, I found that the original data did not match the properties of the field jade ore. The original cause statement was difficult to explain the phenomenon observed on the spot, which aroused my interest in thinking about the causes. Furthermore, the discussion of causes is to summarize the rules and seek new mineral resources. With a realistic cause hypothesis, it is definitely helpful for finding new resources. Based on this idea, I would like to put forward a macro perspective for everyone to discuss.

1. The theory of the cause of jade and its controversy

There are many opinions on the causes of jade in serpentinite or serpentine petrochemical peridotite. In summary, there are roughly three types of magma theory, metamorphism theory and hydrothermal explanation theory. The three theories have certain theoretical reasons, but any theory cannot explain objective geological phenomena or even contradictions. The magma theory believes that jade is under high pressure conditions, and the acidic molten body and superbasic rocks lose silica, enriching magnesium, calcium, iron and chromium, thus forming a band-shaped jadeite sodium long rock with contact reaction edges. The problem is where did the silica go? It cannot explain jadeite.

There is a clear boundary between the ore and surrounding rock. Metamorphosis, jade is formed by decomposing sodium feldspar into jade and quartz. Many people also used chemical reaction formulas to illustrate it. This time, we observed and identified under the field and under the indoor mirror that there was no sign of sodium feldspar decomposing to jadeite. There was no silicification in the ore body and surrounding rock. Where did quartz go? It was said that jadeite was formed by the interpretation of granite rocks and superbasal rocks. According to this, jadeite ore should be produced in the contact zone between granite rocks and superbasal rocks, and this is not the case in the jadeite mineral output.

If a mineralization hypothesis cannot explain the actual wild production of ore deposits, it is inevitable to cause controversy. There are so many hypotheses that cannot perfectly explain the actual wild production of jade. What is the problem? Is jade really so mysterious and unpredictable? I think it is artificial to complicate the problem, and it depends on the problem regardless of stages. Just as when studying the causes of marble, the causes of limestone and the causes of marble are studied together, so deep-sea sedimentation, shallow sea sedimentation, coastal sedimentation, regional metamorphism, hydrothermal metamorphism and other causes will occur.

2. Discussion on the causes of jadeite in stages

Everyone knows that the main mineral components of jadeite and jadeite rock are jadeite. In terms of material components, the two are inseparable. However, recent research has shown that there are differences in physical properties, so some scholars have recently clearly stated that jadeite is not equal to jadeite. Not to mention the comprehensive information, just take the 3,000 tons of huge jadeite I just introduced, as for example, the center of the big jadeite has white and coarse grains. The jadeite is self-shaped columnar, loose and opaque. At the inspection site, there were colleagues saying that this cannot be called jadeite, it can only be called jadeite. The edges appear in the purple color, stripe-like green, jadeite mineral particles become thinner, and there is obvious later structural backlog, mineral orientation arrangement, secondary minerals increase, and jadeite is slightly transparent-transparent. Someone shouted loudly at the scene, and these are jadeite.

Since there is a difference between jadeite and jadeite rock, the cause discussion should also be divided into stages. The author believes that it should be divided into diagenetic stages and jadeite stages to explore its causes.

1. Diagenetic stage

The formation of jadeite rock, based on the information I have mastered and this field investigation in the Pagan area, is believed to be the cause of magma, and it is a new magma theory, that is, jadeite rock is formed by primitive magma crystals, a silicate melt composed of hydroneum jade, and is a slightly silicon-poor alkaline magma. For details, its cause is found in "Journal of Gem and Baoxue" Volume 2, 2000, Issue 3, Issue 16-20. What I want to add is that this article still includes jadeite and

Jadeite rock is a convergence; hydronephrite silicate melt is homologous to superbasal magma. During the same period, it only means "birds of a feather flock together", that is, magma differentiation. It means that hydronephrite silicate melt does not invade the superbasal magma in a single magma activity to form jadeite rock, based on the cross-curve boundary between the jadeite and surrounding rock. Otherwise, it is difficult to explain the reality that jadeite is only produced in serpentine or serpentine petrochemical peridotite.

The earth tectonic environment formed in the diagenetic stage: related to subduction or collision, and is produced in the plate tectonic subduction zone; jadeite is in the ultramatter rock, and lanamide schist appears around the ultramatter rock. From the perspective of double metamorphic zone, it is a low-temperature and high-pressure metamorphic zone. These earth tectonic environments formed by jadeite must be locked, otherwise it is difficult to explain why jadeite is in the ultramatter rocks in the Pagan area, but there is no jadeite in the ultramatter rocks in other places.

2. Jade-making stage

The jadeite rock has undergone a major improvement in its physical properties (color, transparency, etc.) after the late dynamic metamorphism and hydrothermal metamorphism, forming jadeite with ornamental and economic value (i.e. jadeite). Dynamic metamorphism mainly causes the jadeite to deform, break, mylonite barcrystal, arrange in a direction along the extrusion direction, and the particles become thinner, etc. These changes increase the transparency of jadeite rock. Everyone knows that medium and high-end jadeite jewelry, one is the fine-grained structure or cryptocrystal structure, the other is the high uniformity of jadeite particles; the third is the high-oriented mineral arrangement, these are the "types" of jadeite jewelry, and the main reasons for good water.

The Pagan area has a dynamic metamorphism after diagenesis. In a large number of jadeite rough stones, signs of tectonic activity can be seen from observations under the micro-region. The geological community agrees that the Pagan area is in the subduction zone of the plate, and this area has strong multi-period tectonic activities. It is said that this area has a dynamic metamorphism after diagenesis, which may be accepted by everyone.

Hydrothermal metamorphism causes jadeite rock to recrystallize, produce late jadeite, and the melting of color-induced elements makes jadeite have beautiful colors; the major changes in structural structure cause major changes in the physical characteristics of the original jadeite rock, which makes it completely different, forming a new bright and transparent jadeite (jade). What we call chrome jadeite, chromium-containing jadeite, chromium-rich jadeite and sodium-chromium pyroxene are both late products of hydrothermal metamorphism. Chromium-containing jadeite and chromium-containing jadeite are the main minerals that constitute high-grade jadeite. They are produced in general jadeite or jadeite jadeite in lower grades, and are mostly produced in vein-like shape. The several two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-two-t

As we all know, the green of jade is caused by chromium (Cr), so where does chromium come from? How does it melt into jade? The author believes that the base of chromium is superbasic rock, and the direct carrier of chromium is alkaline horny amphibole produced by the action of acidic rock and ultrabasic rock. Under the action of hydrothermal, horny amphibole and jadeite produce an interpretive effect to diffuse chromium elements into jade, forming chromium jade, so the phenomenon of "green follows black light" is produced. This phenomenon is in jadeite hair material.

It can often be seen above. Why is the cromolecularis determined to be the direct carrier of chromium elements? First, the objective reality of "green follows the black"; second, the cromolecularis in jade has been tested and analyzed indoors, which is rich in chromium elements, and even chromite appears; third, the chromium jadeite was identified in the jade sheet and found that the late chromium jadeite was the product of the interpretation of amphibole and jadeite. The late green jadeite was distributed along the edge of amphibole. Some jadeite hairs can be clearly seen to be distributed intermittently with the green jadeite, showing a strip-like structure.

The Pagan area has multiple diagenetic phases, acidic rock bodies, and multiple phases. Comb-shaped structures are often seen in jade wool or jewelry, which is a proof of hydrothermal activity. From a macroscopic or microscopic perspective, this area has hydrothermal metamorphism, so everyone can also recognize it.

It should be noted here that dynamic metamorphism and hydrothermal metamorphism are not completely separated, but the formation of jade is the result of the simultaneous combined effect of the two.

An expert will later talk about the phenomenon of vertical and horizontal divisions of jade in the Pagan area, which means that the jade produced in the lower part of the ultramafic rock mass is not as good as the jade on the upper part of the ultramafic rock mass; on the plane, the jade in the south is not as good as the jade in the north. The main reason is that the later dynamic deterioration and hydrothermal deterioration are different, the degree of deterioration is high, the jade is good, the degree of deterioration is low, and the jade is poor.

Jadeite rock also produces jadeite rock in Japan, the United States, Russia, Kazakhstan, and Guatemala, and it is similar to the geological environment and conditions of jadeite rock formation in the Pagan area. Why are there no high-quality jadeite in the above areas? I believe that the main lacks the later power and hydrothermal metamorphism, or the later power and hydrothermal metamorphism are weak.

Conclusion
Chapter completed!