Question

The mincrals having silicate chains are collectively called (1) olivine (2) zircon (3) pyroxcne (4) natrolite

Short answer

Pyroxene

Step-by-step solution

Understand the Question

The question asks to identify which class of minerals consists of silicate chains. Silicates can form different structures such as isolated tetrahedra, chains, sheets, and three-dimensional frameworks.

Identify Silicate Chain Minerals

Among the given options, recognize that the structure type is key. Chain silicates or inosilicates form chains of silicate tetrahedra, unlike structures in other types.

Review Options

Evaluate each option: (1) Olivine - forms isolated tetrahedra, (2) Zircon - forms isolated tetrahedra, (3) Pyroxene - forms single or double chains, (4) Natrolite - forms framework structures. Hence, the chain structure corresponds to Pyroxene.

Select the Correct Answer

Based on the structure types, Pyroxene corresponds to silicate chains, making it the correct answer.

Key concepts

Silicate Structures

Silicate minerals make up a large part of the Earth's crust. They are made of silicon and oxygen, forming a structure called a tetrahedron. Each tetrahedron consists of one silicon atom surrounded by four oxygen atoms. Silicate structures can vary widely:

• Isolated Tetrahedra: Tetrahedra are separate from each other. Example: Olivine.
• Chain Structures: Tetrahedra link together to form single or double chains. Example: Inosilicates.
• Sheet Structures: Tetrahedra form flat sheets. These sheets can slide over each other easily. Example: Micas.
• Framework Structures: Tetrahedra are connected in all directions, forming a three-dimensional framework. Example: Quartz and Natrolite.

Understanding these structures is key to identifying mineral types.

Inosilicates

Inosilicates are a specific group of silicate minerals where the tetrahedra form chains. These chains can be of two types:

• Single Chains: Each tetrahedron shares two oxygen atoms with neighboring tetrahedra, forming long chains. Example: Pyroxenes are common minerals with this structure.
• Double Chains: Two single chains link together by sharing additional oxygen atoms. Example: Amphiboles.

Inosilicates are essential in many rock types, especially in igneous and metamorphic rocks. Their chain structures give them unique physical properties and make them distinct from other silicate groups.

Pyroxene

Pyroxene minerals are a significant part of the inosilicate group, characterized by their single-chain structure. Each chain is composed of silicate tetrahedra connected end-to-end. Some key points about pyroxene:

• Composition: Pyroxenes contain elements like magnesium, iron, calcium, and aluminum.
• Structure: The single-chain arrangement makes pyroxenes quite strong and stable.
• Appearance: They typically appear as short, stubby crystals and can be green, black, or brown.
• Importance: Pyroxenes are common in many igneous rocks like basalt and gabbro, and also in some metamorphic rocks.

Recognizing pyroxene involves understanding its distinct properties and role in geological formations.