The jewelry supply chain is a globally intricate network, encompassing the journey from raw material extraction to consumer sales. It involves various phases, including mining precious metals and gemstones, crafting jewelry, and transitioning through intermediaries such as wholesalers and retailers. The complexity is further heightened by the unique characteristics of materials, intricate designs, and the participation of various craftsmen. Global operations bring geographical challenges, necessitating extensive supply networks and compliance with diverse regulations and ethical standards. Consumer demand for transparency and ethically sourced jewelry underscores the importance of understanding material origins and sourcing practices. The industry must ensure precision at all stages to meet modern expectations regarding authenticity, quality, and ethical sourcing, while tackling issues like fraud and counterfeiting. This paper is motivated by the challenges confronting the jewelry industry amid the advent of Industry 4. 0. The incorporation of blockchain technology is essential for a transformative shift towards a more interconnected, technologically advanced sector. Blockchain represents a promising solution, introducing a secure and transparent digital ledger that authenticates jewelry, traces material origins, and supports data-driven decision-making and supply chain transparency. By leveraging blockchain, the jewelry industry can boost consumer confidence and provide verifiable information detailing each piece's journey from production to sale. The decentralized nature of blockchain significantly reduces fraud risks and enhances information reliability, aligning the supply chain with Industry 4. 0's principles. Several researchers have investigated blockchain applications to augment supply chain transparency and integrity. For instance, Abeyratne et al. proposed a blockchain concept for enhanced transparency and traceability in manufacturing supply chains, while Caro et al. compared public and private blockchains to identify their respective advantages.

Other studies highlighted various traceability systems and hybrid blockchain architectures aimed at improving product authenticity and process management. However, many existing blockchain solutions are largely theoretical and lack thorough implementation evaluations. This study, contrastingly, presents a fully operational blockchain-based system tailored for the jewelry supply chain, addressing significant issues related to counterfeiting, transparency, and the complex network of intermediaries involved in the jewelry sector. Counterfeiting presents a critical challenge, as consumers often find it difficult to verify the legitimacy of materials used in jewelry due to the opaque nature of the supply chain. This complexity hampers efforts to track provenance, regulatory compliance, and quality control—issues that are paramount for maintaining consumer trust. The proposed blockchain solution employs Ethereum and smart contracts to enhance traceability, transparency, and authenticity throughout the jewelry supply chain. It documents the entire journey—from mining to retail—on a decentralized ledger, with off-chain certificate templates dynamically populated using blockchain data. This structure curbs fraud risks and empowers all stakeholders to easily authenticate product information. The system is designed to adhere to Industry 4. 0 principles, improving traceability and offering practical, scalable, and cost-effective solutions. Key contributions include an extensive evaluation of the proposed system, showcasing its efficiency and effectiveness compared to existing systems. A detailed comparison highlights advantages such as decentralization, data integrity, and scalability. The hybrid storage solution integrates both on-chain and off-chain data management approaches, ensuring cost-effectiveness and performance while maintaining data security. Stakeholders in this jewelry supply chain system include admins, miners, refiners, manufacturers, retailers, and consumers, each with defined roles and responsibilities facilitated via a user-friendly interface. Smart contracts govern interactions among participants, with strict access controls ensuring the integrity of operations. Security measures are integrated into the design to protect against various vulnerabilities. Implementation of this advanced system also faces challenges, including stakeholder resistance, regulatory compliance, and education about blockchain benefits. Starting with a phased rollout and engaging industry leaders could help ease transitions, while supporting education initiatives will foster technology acceptance. Despite these hurdles, integrating blockchain presents a remarkable opportunity to revolutionize the jewelry supply chain, ensuring enhanced transparency, trust, and efficiency in this vital industry.