Virtually all colours, often modified by additional colours called overtones, and with a pearly lustre. Some pearls also display the iridescent colour phenomenon known as 'orient'.

Treated freshwater cultured pearls have a hardness of only 2.5-4 on the Mohs scale. They also have variable levels of toughness influenced by ageing, dehydration and sometimes excessive bleaching during processing. This means that treated freshwater cultured pearls are prone to scratching and are relatively fragile. They are particularly susceptible to damage caused by acids, solvents and ultrasonic cleaning, and may also have a tendency to dehydrate over time under certain conditions. Some dyed pearls may fade or revert to their original colour when exposed to sunlight or strong light.

Cosmetics should be applied before pearls are worn. Do not expose them to ultrasonic cleaning or high temperatures. Avoid exposing dyed freshwater cultured pearls to strong sunlight or display lighting for extended periods of time. Never soak treated freshwater cultured pearls in water or rub them harshly as this could damage the nacre. Instead, wipe them over with a very soft, clean cloth that has been dampened in lukewarm soapy water. Then pat dry. Your skin’s natural oils and moisture help prevent drying of pearls. So wearing pearls is one of the best ways to keep them looking their best.