Starlight effect: The surface of some cut and polished jewels and jade presents two or more intersecting bright lines, which is the starlight effect. Often four or six beats of star lines. Most of them are caused by dense two-way or three-way needle-like inclusions inside.
Glossy effect: The diffuse reflection effect produced by the light reflected by the inclusions or structural features inside the gem is called the glossy effect. For example, moonstone is an ultra-fine structure composed of orthoclase and albite with slightly different refractive indexes, which produces a floating light blue or white luster, also known as moonlight effect.
Color-changing effect: the phenomenon that the color or a series of colors produced by interference or diffraction changes with different observation directions when light is reflected from some unique structures. Like opals.
Halo effect: when light passes through films or layers with different refractive indexes, the rainbow color produced on the surface or inside of gems is halo effect, such as cryolite and Labrador stone.
Color-changing effect: the phenomenon that the sample shows obvious color change under different light sources is called color-changing effect, which is often observed by sunlight and incandescent lamps.
Placer gold effect: scintillation effect caused by light reflected by fine flaky mineral inclusions inside. The mass per unit volume of a substance.
Relative density: it is the ratio of the weight of a substance to the weight of water with the same volume, and its size is equal to the ratio of the weight of an object to the weight of water with the same volume (4℃), which can also be called specific gravity. There are generally two methods to measure the specific gravity of an object: still water weighing method and heavy liquid method.