Is K9 glass a type of crystal? How to distinguish K9 glass from crystal products?
- Is K9 glass a type of crystal?
K9 glass typically refers to a specific type of optical glass made of K9 material, primarily utilized in optical coatings and various other applications. In comparison to resin, K9 glass demonstrates superior transmittance, refractive properties, hardness, and texture. The principal manufacturing processes include cutting, grinding, polishing, and pressing casting (which necessitates the use of a furnace).
Is K9 glass a type of crystal? How to distinguish K9 glass from crystal products?
It is important to note that K9 glass is not classified as crystal. According to the European Union’s initial definition of artificial crystal, materials must contain more than 24% lead oxide (PBO). K9 glass not only lacks PBO but also does not achieve the refractive index characteristic of leaded glass.
In 1972, the European Union established criteria for lead crystal: any glass with a lead oxide content equal to or exceeding 30%, a density greater than 3 g/cm³, and a refractive index equal to or exceeding 1.545 qualifies as full lead crystal. Additionally, glass containing a lead oxide content of more than 24% can be called lead crystal. However, crystal glass remains vaguely defined and often refers to glass with less than 24% lead content, as glass with a minimum lead oxide content over 24% is permitted with the name of crystal.
- How to distinguish K9 glass and crystal products
K9 glass is a specific type of optical glass with high transparency. Following a series of processing, including cutting, sandblasting and other procedures, the material is characterized by a low level of hardness, a lightweight feel, and a low transmittance. It exhibits a general refractive index of 1.51, a hardness of 5.5 and a melting point below 900 degrees.
- Listening
The sound produced when the two materials are struck with the hand differs. The sound of the crystal products is crisp, similar to the sound produced by striking metal. In contrast, the sound of K9 glass is dull and heavy, with no echo.
- Weighing
The item manufactured from crystal is heavier than the item manufactured from K9 glass, in the case of two items of the same size.
- Observingthe refraction
Crystal products have a higher refraction rate than that of glass when exposed to the same light source. They are also capable of transmitting a variety of light with different colors, which is not a feature of K9 glass.
- Comparing the hardness
The hardness of crystal is greater than that of K9 glass, even artificial crystal will be slightly harder than glass, so using crystal to scratch the surface of the glass will leave a mark, and the crystal will not be damaged.
