Rocks can greatly enhance the appearance of a terrarium! Here are a few ways they contribute:

1. Aesthetic Appeal: Rocks come in various colors, shapes, and sizes, adding visual interest to the terrarium. They can create a natural, earthy look or a more polished, decorative appearance depending on the type of rocks used.
2. Texture and Contrast: Different types of rocks provide texture and contrast within the terrarium. Smooth river rocks, for example, can contrast with rougher succulent plants or moss, creating a pleasing visual balance.
3. Functional Uses: Rocks can serve practical purposes in a terrarium. They can act as drainage layers at the bottom to prevent waterlogging, as barriers to separate different layers of substrate, or as anchors for small plants.
4. Landscaping and Design: Rocks can be arranged creatively to mimic natural landscapes like mountains, riverbanks, or rocky outcrops. This adds depth and dimension to the terrarium, making it more visually engaging.
5. Support for Plants: In larger terrariums or those with climbing plants, rocks can provide support and structure for plant growth. They can also help prevent soil erosion around plant roots.

Overall, rocks are versatile elements that contribute both aesthetically and functionally to the appearance of a terrarium, making it more attractive and conducive to plant growth.