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The properties of the crystal
Jan 09, 2017

Optical properties of

Color: colorless, shallow to deep purple, yellow, medium to dark yellow, shallow to deep brown, brown, green to yellowish green, shallow to pink.

Amethyst: shallow to deep purple.

Topaz: yellow, medium to dark yellow.

Blue crystal: light blue, dark blue. Almost all of the blue crystals are synthetic.

Smoky quartz: shallow to deep brown, brown. Due to the composition of Al3 + replaced the Si4 +, the irradiation after [AlO4] 4 - color heart.

Green crystal: green to yellowish green. Color formation is associated with Fe2 +, almost does not exist on the market of natural form of green crystal, is usually amethyst in heating into yellow crystal in the process of the formation of an intermediate product.

The stone of the lotus: shallow to pink, tonal and shallow. Often due to containing trace amounts of titanium (Ti) elements are pink. Star effect can be transmitted.

Development: colorless, pale yellow, pale brown, etc., but because of containing rutile is golden yellow, brown red wait for color, containing tourmaline often show a film; But the actinolite celadon.

Sheen: glass luster. Fracture for oily luster. Gloss, refers to the stone surface of an optical properties of the light reflection. Watch crystal luster, usable hand holding it, with lights or the window in the surface reflection light, transparent crystal brightness and luster strength.

Transparency: transparent crystal related to quality and quantity of light through it. Minimum thickness is 1 cm light transparent crystal shards or flakes, can see clearly

Refractive index (RI) : 1.544 1.553, almost not beyond this range. (refractive index, is by the air when light penetration, precious stones, crystal and refraction phenomenon, its incidence is sinusoidal and ratio of refraction Angle sine.)

Double discount rate (DR) : 0.009 (maximum), the value is very stable.

The dispersion value: 0.013. Refractive index and lighting light dispersion is said gems of different and have certain changes. Such as diamond to red light refraction is 2.405; The green light is 2.427; Violet light is 2.449.

Light: a shaft is optical crystal. Saw a axis crystal under orthogonal polarization interference figure is unique, and the black cross arm of the center, the formation of hollow pattern, commonly known as the bull 's-eye interference figure. Center part is usually light green or pale pink.

Pleochroism: colorless crystalline pleochroism. Colored crystal has a weak to strong pleochroism. Show the body color shades.

The mechanical properties

Cleavage: no cleavage. Cleavage refers to the mineral is hit, the split along a certain direction there are rules to form a smooth surface properties. According to the degree of cleavage can be divided into five categories: very complete cleavage, complete cleavage, moderate cleavage, incomplete cleavage and no cleavage, crystal belongs to no cleavage.

Fracture: shells. Fracture is also called the crevasse. It refers to the mineral produce irregular broken after being hit, rupture surface uneven called fracture. According to the shape of the fracture can be divided into the shells and jagged.

Hardness: 7, mohs hardness for mohs hardness, quite generally hard steel file. In 1824, a man named frisch. Moss Austria mineralogist, 10 varieties from many minerals, after a scientific experiment to measure their relative hardness, the resulting crystal hardness of mohs 7. Although the use of national bureau of standards, promote more scientific, hardness tester, but the jeweler in many countries in the world, is still used to mohs hardness scale.

Density proportion (SG) : 2.66 (0.03, 0.03) g/cm3. This means that a certain volume, the weight of the crystal is 2.56 to 2.66 times the weight of the same volume of water. The massive variant crystal density may be slightly higher.

Piezoelectric: crystals of stress can be induced in charge; On the contrary, under voltage, the crystal will produce a high frequency vibration. Crystal can make the pressure and charge transfer the performance of each other, called piezoelectricity.

Striation color: colorless. The color of the mineral powder called streaks. It can eliminate the false color, abate his color, keep the color, is one of color is more reliable than mineral identification features.

Melting point: crystal melting point is 1713 ℃. The heat brittle characteristics, it is found in the experiment. Put crystal spray flame burning flame of baking, unless there is a very good protection, and slowly cooling, or crystal easy to fracture. This temperament, the ancients has been through.