My amethyst bracelet has been worn for a year and a half, and the jade pendant has been worn for 25 years. The findings are opaque. The crystal becomes cloudy and dark. The jade pendant is bright but transparent. Amethyst bracelets and jade pendants may become dark and turbid after being worn for a long time for the following reasons:

1. oxidation: crystal and jade pendants may be oxidized after being worn for a long time, resulting in dark colors. If the crystal bracelet is coated, the film may also oxidize and fall off, making the crystal look turbid.

2. Dirt and grease: Dirt and grease secreted by human body may penetrate into the surface of crystal and jade pendants, affecting their transparency and color.

3. Dehydration: Crystal bracelets and jade pendants may be dehydrated if they are left in a dry environment for a long time, resulting in dark colors.

4. Influence of ultraviolet rays: Ultraviolet rays may cause chemical reaction between the crystal and the surface of the jade pendant, leading to dark color.

To restore the luster and transparency of crystal bracelets and jade pendants, you can try the following methods:

1. Cleaning: Wash the crystal and jade pendant with mild soapy water or alcohol, and wipe it clean with a soft cloth.

2. Soak: soak the crystal bracelet and jade pendant in warm water, add a few drops of detergent or soapy water, and then gently wipe with a soft cloth.

3. Waxing: Apply professional crystal or jade care wax on the surface, and then wipe it with a soft cloth to make the wax evenly distributed.

4. Storage: Store the crystal bracelet and jade pendant in a dry, cool and ventilated place to avoid sunlight and ultraviolet rays.

If all the above methods fail, it is recommended to seek the help of a professional jeweler.