Trong tự nhiên, all materials that have bright colors, Tinh thể, và sáng chói; 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. Nói chung, unprocessed […]
