It is obviously jade, so why does it have a glassy luster? I understand!

Anyone who knows a little about jade will be familiar with the term glassy luster . But have you ever wondered how the luster of jade is formed? Why use glass to describe it?

What is gloss?

Gloss refers to the ability of an object's surface to reflect light.

As for precious stones, due to different factors such as the minerals they consist of, their structure, and degree of compactness, their ability to absorb and reflect light is also different. Therefore, when exposed to light, their brightness when presented to the human eye is also different, thus bringing different visual experiences, such as bright, soft, smooth, etc.

Generally speaking, the higher the hardness and density of a gemstone, the higher its brightness . This is because the greater the density, the denser the mineral, the smoother the polished surface of the gemstone, the higher the degree of reflection, and the brighter it is.

Similarly, the way the gemstone surface is cut and the degree of polish will also affect the gloss. If the surface is uneven and roughly polished, it will cause diffuse reflection of light, weakening the light entering the human eye, making it appear dull and discolored.

What are the glosses?

Depending on the intensity of the luster, it can be divided into metallic luster, diamond luster and glass luster . At the same time, affected by factors such as color, smoothness, and structure, some special glosses will also be produced, such as oil, resin, silk gloss , etc.

1

Metallic luster

Gemstone minerals with metallic luster have a metallic surface and are generally opaque . Very few gemstone minerals have metallic luster, such as pyrite, which can have a metallic luster after polishing.

2

Diamond luster

Diamond luster can also be said to be the luster of diamond. Its light is very bright, with a sense of sharpness, transparent to translucent, and is represented by diamonds.

There is a sub-diamond luster under the diamond luster. For example, zircon (synthetic cubic zirconium oxide) and moissanite (synthetic silicon carbide) belong to this category. Although the luster is very strong, there is still some gap with diamond.

3

Glass luster

As the name suggests, glass luster means that the surface is as bright as glass , and it is basically transparent to translucent . Currently, most of the colored gemstones, crystals, jadeite, etc. on the market have a glassy luster.

4

Grease sheen

A special non-metallic luster. When the surface is not smooth, or when the surface is smooth but the minerals are produced in dense block aggregates, the reflected light is scattered and presents a greasy luster.

The most famous jade with oily luster is the high-quality Xinjiang Hetian jade. This luster is very pleasing to the eye, graceful and warm, especially the top-grade mutton-fat white jade, which exudes a luster like mutton fat and is very visually pleasing.

5

Resin gloss

Some yellow to yellowish brown gemstones, such as amber, have a luster similar to that of resins such as rosin on their cross-section.

But if polished very well, amber can also take on a nearly vitreous luster.

6

Waxy luster

A waxy sheen, like the sheen you get on a candle , is typical of turquoise and serpentine jade.

7

Earthy luster

Some finely dispersed porous gemstone minerals, such as inferior turquoise with a high degree of weathering, have a dull earthy luster due to the diffuse reflection or scattering of light.

8

Silky luster

This refers to some transparent gemstone minerals that originally have a glassy luster or adamantine luster. When they appear in the form of fibrous aggregates, or on the surface of some minerals with complete cleavage, they have a silky luster , such as malachite.

9

Pearlescent

A soft and colorful luster seen on the surface of pearls or some light-colored transparent gemstone minerals with well-developed cleavage.

The above gloss level classification does not completely correspond to the reflectivity and refractive index of gemstones. In other words, a kind of gemstone may have multiple glosses . For example, old jade will have an oily and sticky feeling, and if it has been acid-washed, it will have a resinous gloss.

Luster is one of the important properties of gemstones. Experienced people can use the characteristics of luster to eliminate some imitations or conduct preliminary identification of different gemstone varieties.

fruit

fcgc33