Glass is mainly made by melting a mixture of which materials?

Introduction / Context:
Glass is a familiar material used in windows, bottles, and many everyday objects. It is produced industrially by melting raw materials at high temperatures and cooling them rapidly to form a non crystalline solid. Knowing what goes into glass helps link chemistry, geology, and manufacturing. This question asks which combination of materials is typically melted to make ordinary glass, such as soda lime glass used in most windows and containers.

Given Data / Assumptions:

• The options include sand and silicates, quartz and sand, mica and quartz, and mica and silicates.
• We assume common soda lime glass, not special glasses with unusual compositions.
• Sand here refers mainly to silica rich sand composed largely of silicon dioxide.
• Silicates refer to compounds containing silicon and oxygen combined with metal ions.

Concept / Approach:
Ordinary glass is produced by melting silica, usually in the form of sand, together with other silicate materials such as soda ash and limestone, which act as fluxes and stabilisers. Sand provides the main source of silicon dioxide, while additional silicates adjust the melting temperature and properties. Quartz is a crystalline form of silicon dioxide and is related to sand but is not usually listed separately in simple school level descriptions. Mica is a layered silicate mineral used in electrical insulation and other applications but is not a principal ingredient in common glass. The correct approach is to choose the option that recognises sand and other silicates as the key components.

Step-by-Step Solution:
Step 1: Recall that silica sand is the principal raw material for glass, providing silicon dioxide. Step 2: Remember that other materials such as soda ash and limestone are added, which are chemically silicates or related compounds, to adjust melting behaviour and durability. Step 3: Recognise that the phrase sand and silicates summarises this mixture of silica sand and additional silicate materials. Step 4: Note that quartz is itself a crystalline silica and is closely related to sand, but the option quartz and sand is redundant and does not highlight the role of other silicates. Step 5: Understand that mica, although a silicate, is not a main component of standard glass mixtures and is more often used for insulation rather than bulk glass production. Step 6: Conclude that sand and silicates is the best description of the mixture used to make ordinary glass.

Verification / Alternative check:
Basic industrial chemistry references describe soda lime glass as being made from a mixture of silica sand, soda ash, and limestone. Soda ash and limestone transform into silicate compounds under high temperature conditions. The key idea is that the melt contains silica and other silicates. Although quartz and sand are both forms of silica, manufacturers usually refer to sand as the primary source. Mica is not normally mentioned as a glass raw material. Therefore, the option sand and silicates best matches the real composition used in glass making.

Why Other Options Are Wrong:
Quartz and sand both primarily provide silicon dioxide; listing them together ignores the role of other silicates like soda and lime, so this option does not represent the usual glass making mixture.

Mica and quartz would introduce a layered silicate mineral that is not typically used as a major glass raw material, so this combination is not standard for glass production.
Mica and silicates is also incorrect because while it mentions silicates, it ignores the central role of silica sand and overemphasises mica, which is not a key ingredient in ordinary glass.

Common Pitfalls:
Students sometimes over focus on the word quartz because they know it is a form of silica and assume any option containing quartz must be correct. Others may not differentiate between different silicate minerals and think mica is commonly melted to make glass. Another pitfall is ignoring the role of additional silicate additives and assuming sand alone is enough. To avoid these errors, remember that ordinary glass is based on silica sand with added silicate materials to improve its properties, well summarised by the phrase sand and silicates.

Final Answer:
Glass is mainly made by melting a mixture of sand and silicates.