The level of crystal office supplies is based on the results of the visual inspection without the help of a magnifying glass. There are several levels:
Special grade: the entire crystal office supplies are flawless, and there are no visible human flaws and bubbles.
Level A1: extremely subtle blemishes, or tiny natural inclusions, or no more than 3 mm of fog or cotton wool.
Grade A material: slight blemishes that are easily visible to the naked eye.
Class AB: there is a large cloud cover with small ice cracks and small scratches on the outside.
Grade B: more than half of the crystal is covered with clouds and inclusions, with large ice cracks and small cracks in the surface.
Grade C material: the lowest level, the whole is cloudy, the ice crack marks are obvious, the appearance also has obvious crack, as if can be broken at any time.
At present, the crystal commonly used as office supplies is artificial, usually with K to distinguish grades, K1 ~ K9, the higher the value, the higher the purity. The prices of different grades are very different, the higher the price is, the higher the price will be. If you do not use the instrument, you can distinguish it from the following methods: the brighter the light, the higher the level of light.