The gemstone ruby is predominantly made of corundum, and its signature red color comes from the addition of chromium. The depth of the red color in a ruby is directly linked to the amount of chromium it contains. However, the presence of other elements like manganese and iron can result in an orange hue. In gemology, a ruby is defined specifically as a red-colored stone. In contrast, in laser technology, the term "laser ruby" is used to distinguish between pink chromium-doped corundum and pink titanium-doped sapphire, allowing for the use of the term "pink" in reference to some laser rubies. It's important to note that the rubies discussed here are all of the red variety.