**Abstract**

The use of mineral elements with special characteristics, such as quartz crystals, in ornamental or ceremonial contexts, is not uncommon in archaeology. Their appearance in different archaeological sites is the basis to discuss their significance for past societies. However, while these objects are loaded with symbolic value, it is difficult to identify them in hunter-gatherer sites. In this chapter, we discuss this subject from the case of a series of crystals discovered in the central area of the Big Island of Tierra del Fuego, and we outline their interpretation based on technofunctional analysis confronted with the ethnographic information for the region. Tierra del Fuego is located at the southern tip of South America. It was inhabited by hunter-gatherer societies since the end of last glaciation until the beginning of the twentieth century. In historical times, the central-northern sector of the Big Island was occupied by the Selknam society, in which there is an extensive ethnographic and ethnohistorical bibliography. Archaeological research in the central area of Tierra del Fuego has revealed a continuous occupation of hunter-gatherer societies. The analysis of provenience of raw materials lets us to propose hypothesis about mobility and interaction networks that can be confronted with the ethnographic information.

**Keywords:** interaction networks, ornaments, ceremonial, technofunctional analysis, raw materials
