Earrings in 18k gold-filled are a popular choice because they provide the appearance and quality of solid gold earrings at a more affordable price point. 

The 18k indicates that the gold, giving the earrings a luxurious and high-quality look.

The gold layer in 18k gold-filled earring is thicker than in gold-plated earrings, making them more resistant to tarnishing, fading, or flaking with proper care.