Micaschist or slate is a fine-grained metamorphic rock, characterized by its ability to split easily into thin, flat sheets. The antonyms, or opposite words for micaschist, would be materials that are coarse-grained, nonmetamorphic, and do not split into thin sheets. Some examples of antonyms for micaschist include sandstone, limestone, and granite, which are typically larger-grained rocks that are less easily split into thin sheets. While micaschist and slate may be valued for their durability, hardness, and resistance to weathering, the opposite characteristics of their antonyms may be more desirable for certain applications, such as in construction or landscaping.