Corundum is a very precious gemstone, and it is the most sought-after item in the jewelry category like diamonds. So what color does corundum have?

Classified by color:

  1. Ruby:
    Refers to red corundum gemstones, pink corundum belongs to pink sapphires.
  2. Sapphire:
    Corundum gemstones of all colors except the red series, including pink, colorless, yellow, red, orange, green, blue, dark brown, purple, etc. In addition to the direct naming of blue corundum as sapphire, corundum of other colors must be preceded by color adjectives, such as yellow sapphire and green sapphire.

Special optical effects:

  1. Starlight Ruby, Starlight Sapphire:
    Red and sapphire can contain rich rutile inclusions. These needle-like bodies intersect at an angle of 60 degrees in a plane perpendicular to the C axis. After being processed into a curved gemstone, they will show six star lines.
    The occasional twelve-radius star line pattern is formed by the intersection of two groups of six-radius star lines. According to reports, one of the inclusions that caused two sets of starlight is rutile and the other is hematite.
  2. Color-changing sapphire:
    A few sapphires have a discoloration effect. They are blue and gray-blue in sunlight, dark red and maroon under incandescent lamps. The discoloration effect is generally not obvious, and the color is not too bright.