Red sapphire grading standards are mainly based on 1T and 4C: Transparency, Colour, Clarity, Cut, Carat.
1. Transparency: refers to the extent to which a gemstone allows visible light to pass through.
In the naked eye identification of red sapphire, the transparency is generally divided into five levels: transparent, translucent, translucent, sub-transparent, and opaque.
1. Transparent
It allows most of the light to pass through, and when you look at the objects behind it through the gemstone, you can see clear outlines and details.
2. Subtransparent
It can allow more light to pass through. When observing the object behind it through the gemstone, the outline of the object can be seen, but the details are blurred.
3. translucent
It can allow part of the light to pass through. When observing the object behind it through the gemstone, only the outline shadow of the object can be seen, and the details are not visible.
4. Sub-transparent
Only a small amount of light can pass through the edges of the gemstones, but the objects behind them cannot be seen through the gemstones.
5. opaque
Basically, light is not allowed to pass through, and light is totally absorbed or reflected by the object.
Second, color: refers to the color of the gemstone under natural light.
Since the light source has a great influence on the color of the red sapphire, the method for observing the classification of the red sapphire is clearly as follows:
1. Place the gemstone under a white background;
2. Observed from the gem table;
3. Observe red sapphires under natural light.
Generally, the more pure and sapphire the color of red sapphire, the higher the quality and the higher the value. After combining various factors affecting the color of red sapphire, we divided the red sapphire into five levels, among which the ruby ​​is divided into deep red, red, medium red, light red, and light red; the sapphire is divided into dark blue and blue. Medium, blue, light blue, light blue five. Consumers can simply grade the red sapphire color by simply comparing the five levels of red sapphire.
In color grading, it is necessary to consider the effect of uniformity of color distribution and anti-fire (internal reflection light caused by cutting) on ​​the grading of red sapphire color. Usually, they can raise or decrease the color grade of red sapphire by one sub-level.
Third, cut: including the orientation, type, proportion, symmetry, polishing degree of cutting.
Direction of cut: The mineral crystals of red sapphire are generally barrel, column and plate, as shown in the figure above. The vertical direction of the mineral crystal of red sapphire is called the C axis. It is assumed that a faceted gemstone can be cut into facet X and facet Z, where the table top of X is perpendicular to the C axis, and the table top of Z is parallel to the C axis. From the image on the right, we can see the difference between facet X and facet Z: facet Z obviously has dichroism. Therefore, we should try to make the stone surface of the gemstone perpendicular to the C axis when cutting the rough stone, because the value of the gemstone without dichroism is significantly higher than that of the gemstone with dichroism.
Type of cut: Red sapphire cuts include faceted gemstones and plain gemstones. Larger particles of red sapphire are generally mixed cut. Usually, the crown is cut with a bright shape, which makes the gem show a fascinating anti-fire. The pavilion adopts a trapezoidal cut, which makes the gem take care and gains more. Good color.
The proportion and symmetry of the cut: the color of the red sapphire is the embodiment of its value. In order to achieve bright colors, the cutting angle of the red sapphire does not have a qualitative statement, but the following questions will indeed cut the proportion of red sapphire cut. And symmetry cause no small negative effects:
Obvious asymmetry: Although the asymmetry of red sapphire is inevitable, the obvious asymmetry can seriously affect the light of red sapphire.
Bottom eccentricity: Severe deviation of the facet from the center will affect the uniform reflection of light from the pavilion, and will also adversely affect the anti-fire of red sapphire.
The pavilion is too deep: some lighter faceted red sapphire pavilions are usually cut deeper to deepen the color of the gemstone, which is understandable. However, some darker gems adopt this cutting method in order to take care of themselves, but have a greater impact on the color, and in most cases the price of the gems is calculated by multiplying the weight by the unit price per carat. Therefore, when considering the price of precious stones, you should also consider their pavilion depth.
The pavilion is too thin: too thin pavilion will make the light enter the gemstone and cannot be reflected out, thus forming a larger window area, which is also known as "light leakage", which will also have a greater value for red sapphire. Impact.
Polishing degree: The degree of polishing affects the luster and anti-fire of red sapphire, so it is also an indispensable factor in the evaluation of cutting.
This kind of products is very popular in many countries of the world, Especially in USA and European market. We have exported this kind of garments for many years.the style is simple, comfortable, and suitable for any people. because of with padding,it will keep your body warm all the day in winter. the filling is 100% polyester, Both shell fabric and lining are 100% polyester, too. We can meet your requirements to make any quilted pattern and the filling weight you prefer.
If you are interested in this kind of garments, please let us know.
We trust you do like it.
Quilted Clothes With Padding, Quilted Long Coat,Quilted Jacket ,Quilted Padded Vest , With Button, With Zipper, colorful
Jinan Topline Trading Co., Ltd. , https://www.jinantopline.com