What's the difference between the two categories of minerals?

December 11, 2025 •

4 min read

Did you know that over 90% of the Earth's crust is composed of just one type of mineral, the silicates? Answering what's the difference between the two categories of minerals depends on the classification system used, from chemical composition to physical properties.

Quick Summary

Minerals can be broadly categorized chemically as silicates or non-silicates, or by their properties as metallic or non-metallic. Each system highlights different aspects, such as composition, abundance, conductivity, and use.

Key Points

Silicates dominate Earth's crust: Making up over 90% of the crust, silicate minerals contain silicon and oxygen and are the largest mineral group.
Non-silicates lack silicon: Non-silicate minerals are chemically defined by the absence of silicon and oxygen and include many economically vital resources like gold and halite.
Metallic minerals are conductors: Metallic minerals are typically shiny, good conductors of heat and electricity, and can be easily shaped, unlike non-metallic types.
Non-metallic minerals are brittle: Non-metallic minerals are poor conductors, have a non-metallic luster, and are often brittle, making them valuable for different industrial uses.
Categorization depends on context: Whether classifying minerals chemically (silicate vs. non-silicate) or economically (metallic vs. non-metallic), the method depends on the specific focus, from geological structure to industrial application.

The Chemical Classification: Silicates vs. Non-Silicates

The most fundamental and scientifically robust way to classify minerals is based on their chemical composition and internal structure. This system divides them into two broad groups: silicates and non-silicates. This distinction is critical because silicon and oxygen are the two most abundant elements in the Earth's crust.

Understanding Silicate Minerals

Silicate minerals are defined by the presence of silicon and oxygen, often combined with other elements like iron, aluminum, and magnesium. Their basic building block is the silicon-oxygen tetrahedron ($SiO_4$)$, a pyramid-shaped structure with one silicon atom surrounded by four oxygen atoms. The way these tetrahedra link together determines the specific class of silicate mineral, creating a wide variety of structures, such as single chains, double chains, sheets, and 3D frameworks.

This structural variety accounts for the immense diversity within this mineral group, which includes common rock-forming minerals like:

Feldspar: The most common silicate mineral, making up over half of the Earth's crust.
Quartz: A simple but very common silicate, composed purely of silicon dioxide ($SiO_2$).
Mica: Characterized by its sheet-like structure, allowing it to be split into thin, flat layers.
Olivine: Found in dark igneous rocks and forms as isolated tetrahedra.
Pyroxene and Amphibole: Found in chain-like structures.

A Look at Non-Silicate Minerals

In contrast, non-silicate minerals do not contain silicon and oxygen in their chemical structure. While less abundant in the Earth's crust overall, this category includes many economically significant minerals. They are further organized into several distinct chemical groups based on their primary anion.

Important classes of non-silicate minerals include:

Native Elements: Minerals made of a single element, such as gold (Au), copper (Cu), and diamond (C).
Carbonates: Contain the carbonate ion ($(CO_3)^{2-}$) and are common in sedimentary rocks, like calcite ($(CaCO_3)$).
Oxides: Form from a metal and oxygen, such as hematite ($(Fe_2O_3)$).
Sulfides: Contain sulfur combined with a metal, including important ores like pyrite ($(FeS_2)$) and galena (PbS).
Halides: Minerals containing a halogen ion, like halite (NaCl) or table salt.
Sulfates: Contain the sulfate ion ($(SO_4)^{2-}$), with gypsum ($(CaSO_4 · 2H_2O)$) being a key example.

The Economic Classification: Metallic vs. Non-Metallic

Another common way to categorize minerals is based on their physical properties and economic use, dividing them into metallic and non-metallic types. This classification is widely used in resource extraction and industry.

Characteristics of Metallic Minerals

Metallic minerals are valued for their metal content and are a source of metal upon extraction. They possess specific characteristics that differentiate them from their non-metallic counterparts:

Luster: They typically have a characteristic shine or metallic luster.
Conductivity: They are good conductors of heat and electricity.
Malleability & Ductility: They can be hammered into thin sheets (malleable) or drawn into wires (ductile).
Examples: Gold, silver, iron ore, and copper are all examples of metallic minerals.

Properties of Non-Metallic Minerals

Non-metallic minerals do not contain metal in their chemical composition and are not used for extracting metal. Instead, they are exploited for their unique physical or chemical properties.

Luster: They have a non-metallic luster, such as dull, glassy (vitreous), or earthy.
Conductivity: They are poor conductors of heat and electricity.
Brittle: They lack malleability and ductility, and will break easily when stressed.
Examples: Limestone, gypsum, quartz, and mica are common non-metallic minerals.

Silicate vs. Non-Silicate: A Comparative Table


Feature	Silicate Minerals	Non-Silicate Minerals
Composition	Contain silicon (Si) and oxygen (O) in their structure	Lack silicon and oxygen in their structure
Abundance	Make up over 90% of the Earth's crust	Comprise the remaining portion of the Earth's crust
Building Block	The silicon-oxygen tetrahedron ($SiO_4$)	Varied building blocks depending on the class
Sub-classes	Nesosilicates, inosilicates, phyllosilicates, tectosilicates, etc.	Native elements, sulfides, carbonates, halides, etc.
Examples	Quartz, Feldspar, Mica	Gold, Halite, Calcite, Gypsum

Metallic vs. Non-Metallic: A Comparative Table


Feature	Metallic Minerals	Non-Metallic Minerals
Composition	Contain one or more metallic elements	Do not contain metallic elements
Luster	Shiny, metallic luster	Dull, earthy, or glassy luster
Conductivity	Good conductors of heat and electricity	Poor conductors (insulators)
Physical Properties	Malleable and ductile	Brittle and non-ductile
Examples	Iron ore, Copper, Gold	Quartz, Limestone, Mica

Conclusion: The Multiple Ways to Categorize Minerals

In conclusion, the categorization of minerals is not singular but depends on the criteria used, most prominently chemical composition or economic value. The chemical classification into silicates and non-silicates is fundamental to mineralogy and explains the vast differences in rock-forming minerals. Meanwhile, the distinction between metallic and non-metallic minerals is highly practical for resource extraction and industrial applications. Both systems are vital for understanding the complex world of geology and how we use Earth's resources every day. While silicates form the vast bulk of our planet's crust, the diverse array of non-silicates and economically vital metallic minerals demonstrate that every category, regardless of abundance, plays a crucial role.

For more detailed information on mineral resources and geology, the OpenGeology textbook offers extensive resources.

Frequently Asked Questions

The primary chemical classification is based on the presence or absence of silicon and oxygen. Silicate minerals contain both, with the silicon-oxygen tetrahedron as their basic unit, whereas non-silicates do not.

Non-silicate minerals include native elements like gold, carbonates such as calcite (found in limestone), sulfides like pyrite, and halides like halite (table salt).

Metallic minerals generally have a shiny luster, conduct heat and electricity well, and are malleable and ductile. Non-metallic minerals are non-lustrous, are poor conductors, and are typically brittle.

Diamond is a non-silicate mineral. It is a native element mineral, composed entirely of carbon, and does not contain silicon and oxygen in its structure.

The silicon-oxygen tetrahedron ($SiO_4$) is the fundamental building block for all silicate minerals. The way these tetrahedra bond together determines the crystal structure and physical properties of the resulting silicate mineral.

Non-metallic minerals are used extensively in industries. Examples include limestone for cement, gypsum for plaster, mica for electrical insulation, and halite (salt) for de-icing and chemical production.

Different classification systems highlight different aspects of minerals. Chemical classification (silicate vs. non-silicate) is important for understanding geological formations, while economic classification (metallic vs. non-metallic) is more relevant for resource management and industrial use.