Also known as convex surface or plane, its observation surface is convex. According to the waist shape, it can be further divided into circle, olive shape, heart shape, rectangle, square, cross shape, cushion shape, pituitary shape and so on. According to the type of cross section, it can be divided into five types: single convex section, double convex section, lentil convex section, hollow convex section and concave section.

Faceted type

It consists of a series of geometric planes that completely cover the surface of the gem. When polished at a proper angle, gems can show four optical effects: body color, brightness, fire color and sparkle. Faceted type can be divided into diamond cutting, step cutting, rose cutting, scissors cutting and mixed cutting.

Bead type

Commonly used in low-grade gemstones, can be used for different jewelry. It can also be divided into round beads, oval beads, flat round beads, rectangular beads and other types according to their shapes.

irregular shape

Including free type and random type, it can show the ever-changing natural form of gems.