Unheated Yellow sapphire 3.90 caratyellow sapphire An unheated yellow sapphire weighing 3. 90 carats could hold significant value, especially if it has good clarity, color, and cut. Unheated gemstones are often prized for their natural beauty and rarity compared to heat treated counterparts. Its essential to have it evaluated by a gemologist to determine its quality and potential worth accurately.