In nature, all materials that have bright colors, 결정체, and brilliance; pure texture, hard and durable; excellent craftsmanship; rare characteristics that can be processed into jewelry and handicrafts can be called gems. These materials include: natural mineral crystals (single crystals and crystal aggregates), amorphous rocks, and natural organic materials and man-made materials. 일반적으로 말하면, unprocessed […]
