It really depends on the definition of “fine jewelry”. Usually the term “fine jewelry” is used for any jewelry that is made from precious metals such as gold, silver, or platinum. Stone wise, sometimes lab created diamond is paired with natural precious gemstones such as ruby or sapphire. Would you say that a ring with lab diamond, natural sapphire and set in 14k gold is not fine jewelry? I think not.
Trend wise growth we are seeing significant growth in non diamond engagement rings and sales engagement rings with synthetic diamonds are going through the roof while sales of natural diamond are in decline. An interesting read on the topic from CNN Business here.