colorless

Colorless describes substances that do not display hue in the visible spectrum. In practical terms, a colorless material transmits or reflects light without imparting a noticeable color. Colorlessness is not the same as transparency or translucency; a material can be colorless yet opaque or can be transparent but colored by impurities.

Common colorless liquids include water, ethanol, and acetone. Colorless solids include many crystals and minerals such as quartz, as well as uncolored glass and diamonds in their pure form. The appearance of color in a material often arises from selective absorption of certain wavelengths by impurities, transitions metals, organic pigments, or structural features.

Colorlessness can be altered by impurities, concentration, and the path length of light. Even trace amounts of metal ions or organic dyes can give a material a noticeable color. In spectroscopy and analytical chemistry, colorless solvents are sought because they do not interfere with absorption measurements in the visible range; impurities and coloration can complicate readings.

In everyday and industrial contexts, colorless materials are valued for neutrality and clarity. They are widely used in optics (clear glass and lenses), in chemical analysis (colorless solvents and reagents), and in decorative or design applications where true color neutrality is desired.