Crystal Structure of Sapphire, the King of LED Substrates

Crystal Structure of Sapphire, the King of LED Substrates

1. What is sapphire?

As the king of LED substrate, the name of sapphire is from Latin Spphins, which means blue. It belongs to the corundum group mineral, with cubic crystal system. In the gem world, all kinds of gem grade corundum other than ruby are called sapphire. Sapphire, ruby, emerald, goldwater Bodhi, tourmaline, Tanzanite and so on are all belong to the genus of colored gemstones.

Containing iron (FE) and titanium (TI) and other trace elements, corundum presents blue, sky blue, light blue and other colors. Among them, royal blue and cyan are the best.

The mineral name of sapphire is corundum, which belongs to corundum group. In fact, in nature, except for rubies, corundums of other kinds of colors, such as blue, light blue, green, yellow, gray and colorless, are all called sapphire, or color sapphire, that is, adding the color name before the sapphire, such as pink sapphire. The main component of sapphire is alumina (Al2O3). The blue sapphire is due to a small amount of titanium (TI) and iron (FE) impurities.

2. Crystal structure of sapphire

As the one of the best sapphire substrate manufacturers, let Cryscore introduce sapphire's structure. 

The sapphire crystal structure is hexagonal. The crystal morphology is usually cylindrical, short columnar, plate-shaped, and the geometry is mostly granular or dense block. It's transparent to translucent, and has glass luster. Its refractive index is 1.76-1.77, and birefringence is 0.008. It has strong dichroism and heterogeneous. Sometimes it has a special optical effect, starlight effect. The hardness is 9 and the density is 3.95-4.1g/cm3. It has no cleavage or fracture. Because of the characteristics of sapphire crystal structure, when sapphire is cut and ground to arc shape, its interior is rich in three groups of inclusions parallel to the bottom and directionally arranged, which can produce beautiful six ray starlight, so it is also called starlight sapphire.

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