Blue sapphire's pleochroic colors typically include which of the following?

Blue sapphire is known for its beautiful and saturated hues, primarily in the blue spectrum. Pleochroism is the optical phenomenon where a gemstone exhibits different colors when viewed from different angles. In the case of blue sapphire, the typical pleochroic colors one might observe are slightly greenish blue and slightly violetish blue. This characteristic arises due to the crystal structure and the presence of trace elements within the sapphire.

The presence of slight color variations, such as a greenish blue or a violetish blue, is indicative of the crystal's behavior in terms of light absorption and transmission. While blue is the dominant color of sapphires, the presence of these subtle tones reflects the variation in electronic transitions that occur within the gemstone’s crystal lattice. Consequently, recognizing these pleochroic colors is essential for gemologists in accurately identifying and assessing the quality of blue sapphires.