amphibole
Amphibole, an important group of generally dark-colored rock-forming inosilicate minerals, composed of double chain SiO4 tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures. (e.g. asbestos)
A silicate mineral that shares it's oxygen atom with another silica tetrahedron, forming a chain of tetrahedra. Single chain silicates include a group called the pyroxenes.
Hornblende has a double chain silicate structure. This structure consists of pairs of linked tetrahedra that form continuous chains in two dimensions.
The six main crystalline structures of silicate minerals are isolated tetrahedra, single chain, double chain, sheet, framework, and ring structures. Each structure is based on how the silicate tetrahedra are arranged and linked together in the mineral's crystal lattice.
When two single chains of tetrahedra bond to each other, they form a double chain structure. This arrangement creates a stronger and more stable crystal lattice compared to the individual chains.
Hornblende and other amphiboles have a double chain silicate structure, where silicon-oxygen tetrahedra are connected in double chains linked by other cations like aluminum, magnesium, and iron ions. This structure gives amphiboles their distinct prismatic shape and cleavage properties.
a double chain silicate is
double chain silicate
All silicate minerals are composed of silicon and oxygen atoms arranged in a tetrahedral structure. These tetrahedra can be linked together in various formations to create different silicate mineral groups, such as sheet silicates, framework silicates, and chain silicates. Silicate minerals are the most abundant group of minerals in the Earth's crust.
The mineral family that tends to form long needlelike crystals is the amphibole group. Examples of minerals in this group include hornblende and tremolite. These minerals are silicate minerals with a double chain structure, which contributes to their characteristic needlelike crystal habit.
double chain silicate
Chain silicates have interlocking chains of silicate tetrahedra. When adjacent tetrahedrons share either two oxygen's to continue the chain, or three oxygen atoms to connect also to a second chain, double chains are formed.