The short answer is yes!
Many people are mistaken in thinking that a diamond is an investment. Sadly, a used diamond is like a used car, the minute you buy it the value goes down. In fact, the depreciation of diamonds is so great that most jewelry stores won’t buy back diamonds.
Don’t believe me? Ask your local jeweler what he would appraise your diamond jewelry for then ask him if he’ll buy it for that price. Sadly, the appraisal price is what it would cost to purchase a replacement on the retail market. Diamond jewelry resells at roughly 25%-35% of its retail value. Moissanite retail value is also much higher than its resale value but the news here is somewhat better, moissanite can be resold for 50%-60% of its purchase cost.