Oxygen's color depends on its state:
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Gaseous Oxygen: Oxygen in its gaseous state, as we breathe, is colorless, odorless, and tasteless. This is its most common form. [Source: PubChem, Chemistry Hall]
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Liquid Oxygen: Liquid oxygen exhibits a pale blue hue. [Source: PubChem, Reddit - askastronomy, Chemistry Hall]
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Solid Oxygen: Solid oxygen displays a range of colors, including shades of blue, red, and even black-metallic, depending on the specific crystalline structure and conditions. [Source: Chemistry Hall]
It's important to note that the color we perceive is often influenced by the way light interacts with the substance. The pale blue color of liquid oxygen, for instance, is due to light absorption and scattering within the substance itself. While oxygen plays a vital role in many biological and astronomical processes—such as the reddish hues seen in some auroras [Source: National Park Service]—the oxygen itself is not directly responsible for the colors we observe in those phenomena. The red color in meat, for instance, comes from oxymyoglobin, which involves oxygen but is not the color of oxygen itself. [Source: USDA]
Additionally, the color of blood is red due to hemoglobin's iron content, not the oxygen it carries. [Source: NPR]
