1. Color: Topaz is light yellow, and it can show different shades of yellow, from light yellow to bright yellow. The color of jadeite is usually light green or dark green, with rich green tones.
2. Composition: Topaz is mainly composed of silicate minerals, which contains a high proportion of silicon dioxide. Emerald is mainly composed of jadeite, which belongs to sodium magnesium aluminum and sodium iron aluminum silicate minerals, and usually contains a certain proportion of chromium and iron.
3. Features: Topaz is usually hard and transparent, and sometimes it can show some effects of interaction with light. Jadeite usually has high hardness, and sometimes it shows special light effects, such as "glass species" and "oil species" of jadeite.
To sum up, the difference between topaz and emerald mainly lies in color, composition and characteristics. They all have unique aesthetic feeling and value, and are widely used in jewelry, handicrafts and other fields.