CMA symbol is the abbreviation of China Metrology Accreditation. Generally speaking, it is made of natural materials (minerals, rocks, organisms, etc.). ) gold and silver. Jewelry, handicrafts or other treasures with certain value are collectively referred to as jewelry, so it is called "gold and silver jewelry", and jewelry stores that handle these items are also collectively referred to as "jewelry stores". Scientifically speaking, the concept of "jewelry" is the same as "gem" in a broad sense. Gems in a broad sense generally refer to those raw materials suitable for polishing or carving into jewelry or handicrafts.

Gems in a broad sense generally refer to those raw materials suitable for polishing or carving into jewelry or handicrafts. Yuyuan Garden and Jewelry are the most comprehensive and numerous jewelry collection websites at present. Jewelry generally includes: natural jewelry jade (natural gemstones, natural jade and natural organic gemstones), artificial products (artificial gem, recycled gemstones, assembled gemstones and synthetic gemstones), and precious metals for jewelry: gold, silver and platinum.