Explanation:

- Bronze: This is not a mineral. It's an alloy made primarily of copper and tin. Therefore, it's not a natural constituent of the Earth's continental mass.

- Copper: While copper is a natural mineral, it is not one of the main constituents of the continental mass. It's present in much smaller quantities.

- Silica: Silica, or silicon dioxide, is a major component of the Earth's crust, predominantly found in the form of quartz and other silicate minerals. The crust is rich in silicates, making it a main mineral constituent of the continental mass.

- Gypsum: This is a mineral composed of calcium sulfate dihydrate. It's useful in various industrial applications but isn't a primary constituent of the continental mass.