One of the largest sapphires is known as the Star of Asia, which is currently housed at the Smithsonian Museum of Natural History.
Star Sapphires And Color Change
Another unique attribute of sapphires is asterism. Asterism, also known as “the star effect”, is a phenomenon that can occur in corundum. Asterism appears as a six-ray star pattern across the surface of the stone. It can appear in both sapphires and rubies.. The star effect comes from the reflection of light off of a great many tiny, needle-like inclusions across the stone.
There are also “color-change” sapphires. These strange and lovely stones change color under different lighting! One of the more common types of color-change sapphires are stones that will appear to be blue or have fluorescent lighting in daylight, and can shift to purple hues under incandescent light.