I. Geological Formation: Nature's Billion-Year Craftsmanship
Three-Stage Evolution:
Primary Formation: Silica-rich hydrothermal fluids fill volcanic cavities, forming agate veins/balls.
Transportation: Floods detach protoliths; river abrasion rounds them into pebbles.
Deposition: Settled in Yangtze/Dongting Lake beds over 1.5–2.5 million years.
Key Sources: Nanjing Yuhuatai (legendary origin), Three Gorges & Dongting Lake (large, vivid stones).
II. Scientific Classification & Material Properties
Official Categories (Jiangsu Standard):
| Type | Composition | Features | Grade |
|---|---|---|---|
| Rainflower Jade | Cryptocrystalline Quartz | Translucent, smooth | Gemstone-grade3 |
| Agate Rainflower | Banded SiO₂ | Circular patterns | Premium collectible |
| Quartzitic Rainflower | Macrocrystalline Quartz | High hardness (Mohs 7) | Mid-range |
| Fossil Rainflower | Silicified remains | Ancient biological structures | Scientific value |
Aesthetic "Six Beauties": Texture, Form, Vein, Color, Imagery (landscape/figure patterns), Artistic Conception.
III. Cultural Significance & Market Innovations
Heritage: Zhou Dynasty records; 1990 Nanjing Museum establishment.
Cutting-edge Applications:
PV glass sand purified from low-value pebbles (value ↑10x).
Custom agglomerate tiles (e.g., Disney-themed pavements).
IV. Collector's Advisory
Rarity Metric: "One treasure in 100 tons".
Ethical Sourcing: IGA's "1-ton-mined: 3㎡-repaired" standard.
"Rainflower stones are poetry in geological time – each vein etched by Earth's pulse, each hue whispering nature's philosophy."