Some basic knowledge of jewelry beads

For most DIY craft beads, jewelry are the most commonly used materials, while their design projects. In fact, some pearls as common as resin beads, glass beads, European beads pearls and precious stones are not a simple substance. To purchase the most fickle for DIY projects may not be as difficult for the person practiced, but for the majority of pupils in primary schools, choose the beads and charms is really a big problem, which will lead to some problems after the use of inappropriate ones. In this article, I will make a brief introduction of the basic physical properties of the beads'!
1. Refractometric
Definition: Refractive index is ie the ratio between the speed of light in air against that in the materials. The higher the refractive index of the material, the strong ability intends to refract light. To make judgments more directly, you can follow the methods: make use of a book, each book contains the words is ok. Then put the beads on the word (certainly the pearls and pendants must be transparent), the most clear of words means that the smaller the refractive index. A comparison experiment is the difference between crystal and transparent corundum, their refractive index are 1.55 and 1.77 respectively. When he put the glass on the word, the word has very clear, but fails the transparent corundum.

2. Transparency
In general, it can be divided into four categories: transparent, translucent, sub-translucent, not transparent.
First: transparent, the most famous precious stones such as diamonds and crystal are all belong to this category.
Secondly, translucent, like Tourmaline, while placing it on the words, you can only see the big outline.
Third, sub-translucent. The most typical example is the jade. And 'permeable to light, but the sight of men able to see some of it.
Forth: opacity. Most of the beads and pendants for example malachite obsidian and are part of this system. In addition, the recently popular beads like pearls on clay are regularly opaque.
3. Pleochroism
In summary, the pleochroism is precisely on a gemstone, sometimes you will present different shades. This optical phenomenon may appear only on special colored gems that have more than one refractive indepear the lights pass through different positions, will be reflected in multiple directions, then the hue will present different.
4. Dispersion
As we know that white light (natural light) is made up of red, orange, yellow, green, blue, indigo and purple ones, dispersion refers to the phenomenon that when the natural light has been fixed in the original seven lights, for example the rainbow is also the result of the dispersion.
5. Density and specific gravity.
Initially you need to understand the definition of these two words, the density, the mass per unit volume of precious stones (g / cm ³), the specific gravity is the ratio of the weight of the ring in the air and in water 4C, the two figures may be the same.
6. Hardness
The hardness is, as the name suggests, how hard is the gem. A common use is the Mohs scale. In general, from top to bottom are: Adamas (diamond), corundum (ruby, sapphire), Topaz (blue topaz, palmer stone), quartz (crystal); stone growth; Apatite (moonlight stone) Fluorite, Calcite (State ice stone); plaster. Talc
But in the graph, this is a relative hardness, the hardness is not exact absolute gem itself.