GP jewelry may refer to several different brands or designers. Here are a few possibilities:

• Gucci Jewelry - Gucci is a well-known luxury fashion brand that also produces high-end jewelry. The brand's jewelry is often marked with "GP" (Gucci Paris) as a hallmark.

• Gianfranco Pampaloni - Gianfranco Pampaloni is a high-end jewelry designer based in Florence, Italy. His jewelry is often marked with "GP" as a signature.

• Gold-Plated Jewelry - "GP" may also refer to gold-plated jewelry, which is made by layering a thin coat of gold over a base metal. This type of jewelry is often marked with "GP" to indicate that it is not solid gold.
Without further context, it is difficult to determine which GP jewelry is being referred to.