1 carat diamond weighs 0.2 grams. Hope Diamond weighs 44.4 carats. So, the weight of the Hope Diamond in grams can be obtained by multiplying 44.4 by 0.2. So, we have 44.4 * 0.2 = 8.88 grams. Therefore, Hope Diamond, he world's largest blue diamond weighs 8.88 grams.