We all know that gemstones are actually a kind of mineral, but there are more than 3,000 minerals found in nature, and there are only 230 kinds of gemstones, and only 20 of them can be called high-grade gemstones on the market. . It can be seen that not all minerals can be gemstones. Only minerals with certain specific conditions can be called gemstones. These conditions are beauty, durability and rarity.
As one of the four famous jade in China, Hetian jade has been sought after and loved by people for thousands of years. What excels in it, not only stand out from the major minerals, but also become the leader in the high-end gem world. What about it? Today we will talk about its beauty and durability, namely transparency and resilience.
Toughness refers to the resistance of jade to external pressure or crushing force. It is expressed as the degree of deformation of the jade under a certain pressure until the moment before breaking. It can also be said to be the intrinsic bonding ability of jade. The types of jade are different, and their resistance to smashing, hitting and breaking is also different. The jade with high toughness is not easily broken and wear-resistant. This is different from the hardness of jade. Jade and gemstones of similar hardness have some toughness, some have low toughness and are brittle.
Black diamond is the most resilient mineral in the world. If the toughness of black diamond is 10, the relative toughness of other jade is different. Nephrite is 9, ruby, sapphire, jade is 8, aquamarine, crystal, diamond is 7~7.5, olivine is 6, emerald is 5.5, citrine gemstone, moonstone is 5, opal is 3, fluorite Is 2. It can be seen that the toughness of nephrite is very large. If the softness of the nephrite is 1000, the toughness of other minerals or rocks is relatively: jadeite 500, serpentine 250, quartzite 10~20, quartz 5, corundum 3, mica 2. Nephrite has great toughness, which is inseparable from the felt-like interwoven internal structure of nephrite.
The toughness of jade in foreign countries is divided into five levels, namely special grade, excellent grade, good grade, good grade, very poor grade, and nephrite belongs to special grade. Hetian jade (nephrite) has great toughness. Even under the heavy hammer, it is difficult to knock a small piece of sample. This feature is not available in other jade. It is worth mentioning that the compressive strength of nephrite is even larger than that of steel. A data test shows that the compressive strength data of Russian nephrite is 7759kg/cm2, and the compressive strength of nephrite in Canada is 324~. 4310kg/cm2, these values ​​vary greatly due to the natural cracks in the jade in the specimen.
The compressive strength of Hetian jade was determined as:
Sapphire 2527~5427 (kg/cm2)
Qingbaiyu 3887~6541 (kg/cm2)
The change in these data is also due to the presence of cracks inside the specimen. Hetian jade has great toughness and can be carved with fine craftsmanship. This is very beneficial for the jade shape and honing. The jade jade craftsman can make fine work on Hetian jade without damage.
Transparency is the extent to which jade absorbs light, which is the extent to which jade is visible. Minerals generally divide the transparency of minerals into three types: transparent, translucent, and opaque. In the jade industry, the transparency of jade is also considered to be more important. There are also common words that describe transparency. For example, the transparency is called “the spirit of the earth†or “the pit spirit†and the “water headâ€; the poor transparency is called “the groundâ€. Bored, "pitted", "no head". Because the transparency of jade plays a role in the texture and color of jade, it is more aesthetic, so the same kind of material is better for the water head. However, the water head is only relatively speaking, opacity is not good, too transparent is not necessarily good.
When judging the transparency of jade, it is necessary to polish the jade, and it is divided into four levels of transparent body, translucent body, micro-transparent body and non-transparent body according to the case of seeing other objects under normal thickness. Hetian jade is a micro-transparent body that transmits light at normal thickness, but does not see the transmitted image. Of course, if the white jade is very thin and thin, only 2 mm, you can see the image. There are differences in the transparency of different varieties of Hetian jade, and the general color is lighter than the darker color. Therefore, it is generally not advisable to make the white jade too thin, but the sapphire can be used as a thin tire product.
The above is the knowledge about the toughness and transparency of Hetian jade. Of course, the value of Hetian jade is not limited to this. In addition to transparency and toughness, its luster and color are also very attractive. As one of the indicators of durability, the hardness is not bad. Of course, the most important thing is the role and meaning of Hetian jade in China's thousands of years of history. These are the reasons why it can stand in the ranks of high-end gems for thousands of years.
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