What substance was used in ancient Egypt to stain the hair and nails a rich, warm red?

In ancient Egypt, henna was the substance used to stain hair and nails a rich, warm red. This plant-based dye, made from the leaves of the henna plant (Lawsonia inermis), has been utilized for thousands of years for its vibrant color properties and conditioning effects on hair and skin. Egyptians valued henna not only for its aesthetic appeal but also for its cultural significance, often associating its use with beauty and adornment. Henna can provide a variety of shades depending on the application and the mixture used, but it is particularly known for yielding rich red tones, making it a popular choice for both hair art and body decoration.

While indigo is usually associated with blue hues, carmine is derived from cochineal insects and produces a different kind of red, and beetroot also provides a red pigment but was not historically significant in ancient Egyptian cosmetic practices. Thus, henna stands out as the correct answer due to its specific application and historical relevance in ancient Egyptian beauty rituals.