Antimony is a metalloid, which means it has properties of both metals and nonmetals. It's not classified as a mineral group, but rather a chemical element with the symbol Sb.

While antimony itself isn't a mineral group, it forms a number of minerals, often as sulfides. Some of these include:

* Stibnite (Sb2S3): The most common antimony mineral, it is the primary ore for antimony production.

* Valentinite (Sb2O3): An oxide mineral of antimony.

* Senarmontite (Sb2O3): Another oxide mineral of antimony, with a different crystal structure than valentinite.

* Kermesite (Sb2S2O): A sulfide-oxide mineral of antimony.

So, while antimony isn't a mineral group itself, it's a key component in a variety of important mineral species.