Which characteristic describes vermiculite?

Vermiculite is indeed a hydrous silicate mineral that expands when heated. This property is significant because when vermiculite is subjected to high temperatures, it undergoes exfoliation, meaning it expands dramatically. This expansion occurs due to the water content trapped within its mineral structure; as the heat causes the water to vaporize, the mineral expands and forms lightweight, fire-resistant aerated particles.

This characteristic makes vermiculite particularly valuable in various applications, including insulation and as a lightweight aggregate in construction materials. Its ability to expand contributes to its effectiveness in creating barriers that help with thermal insulation and soundproofing.

Other options do not accurately describe vermiculite. For instance, while some materials may contract when heated, vermiculite’s characteristic is specifically its expansion. Additionally, vermiculite is a natural mineral rather than a synthetic material; hence it does not fit the description of a synthetic roofing material or a waterproofing membrane. Understanding these qualities and properties of vermiculite is essential for its proper application and use in roofing and construction contexts.