Freshwater pearls are all cultivated by freshwater shellfish (mainly Hyriopsis cumingii). The main producing areas are in China. Freshwater pearls are divided into nucleated cultured freshwater pearls and non-nucleated cultured freshwater pearls. Their colors mainly include white, purple, pink and orange. Among them, purple and orange-pink are the colors unique to freshwater pearls. Purple is full of mystery like the vast Milky Way, and "Ultra Violet" is the rating for purple freshwater pearls with the highest quality and the best color.

Chinese Name: 星空紫
English Name: Ultra Violet
Pearl Type : Freshwater Bead Cultured Pearl
Color: Purple
Characteristics: Vivid, with a wide range of sizes and strong luster

Introduction
China is a major producer of freshwater pearls, with its output accounting for 95% of the world's total pearl production. Among them, Zhuji City in Zhejiang Province is the largest base for freshwater pearl farming, processing and sales in China. Its pearl output accounts for more than half of the country's total output and is reputed as the "Hometown of Pearls in China". Freshwater pearls can be divided into two major categories according to different farming types and structures: nucleated cultured pearls and non-nucleated cultured pearls. The structure of non-nucleated cultured pearls is entirely composed of nacre, while nucleated cultured pearls are composed of a pearl nucleus and the nacre that wraps around the nucleus. Since nucleated cultured pearls have a round pearl nucleus, they are generally larger in size and their roundness is also better than that of non-nucleated freshwater pearls.
Evaluation and Grading
The grading of freshwater pearls can be carried out from seven aspects: dimension, shape, color, luster, surface, nacre thickness and matching.

1. Dimension: 2 - 18 mm, common sizes: 2 - 15 mm.

2.Shape：Round，Near-round, Oval，Semi-baroque, Baroque

(Upper row: Nucleated freshwater pearls, Lower row: Non-nucleated freshwater pearls)

3.Color：

Bodycolor：White，Purple，Orangy pink and others

(First row: White; Second row: faint-light-intense-vivid purple; Third row: faint-light-intense-vivid orangy pink)

Overtone：Pink，Green，Violet，Orient

4.Luster：Very good，Good, Fair, Poor

5.Surface: Very good, good, Fair, Poor

6.Nacre thickness：

Nacre thickness of Freshwater Bead Cultured Pearl is usually in the size range of 1.00 - 3.00 mm.

Very good- good ≥1 mm.

7.Matching：Very good, Good, Fair, Poor

Freshwater pearls of the Ultra Violet grade must meet the following conditions:

①Obtain a high-quality grade in the Guild Pearl Grading System:

Roundness/Symmetry: Very Good - Good
Luster: Very Strong - Strong
Surface (Surface Defects): Flawless - Slightly Flawed
Matching: Very Good - Good
Nacre thickness ≥ 1 mm

②The body color is purple.

③The color intensity is Vivid–Strong purple.