If it’s an higher case “L” in addition to a decreased situation “c”, it’s for Louis C Marks who designed jewellery during the 40s. SETA is a corporation that provides manner jewelry. Their jewellery generally features a CZ plating about silver. CN means that the jewellery is manufactured in China, https://garrettcrcmv.elbloglibre.com/37027452/the-definitive-guide-to-jp88