Contents
AI generated euhedral beryl
To understand how mineral compositions can be measured and analysed, it is key tounderstand first what minerals are. In short, minerals are essential natural materials found in various forms in soils and rocks. They form the basic structure of rocks and are vital for many industries, including mining, construction, and electronics. Here we will shortly go through the structure of minerals, properties, and analytical methods.
Minerals are inorganic, crystalline substances with a well-defined chemical composition and a regular atomic structure. The basic unit of a crystalline structure is the unit cell, which, when repeated in three dimensions, forms the mineral's crystal. The classification of minerals is primarily based on their chemical composition and crystal structure.
Minerals have a specific crystal structure determined by the arrangement of atoms. This structure can be described using Bravais lattices, which are three-dimensional, periodically repeating grid models. There are a total of 14 Bravais lattice types, divided into seven main crystal systems:
Crystal System |
Characteristics |
Example Mineral |
Structure Parameters |
Triclinic |
All edges and angles are different |
Plagioclase |
a ≠ b ≠ c, α ≠ β ≠ γ ≠ 90° |
Monoclinic |
One symmetry axis, angles not perpendicular |
Gypsum |
a ≠ b ≠ c, α = γ = 90°, β ≠ 90° |
Orthorhombic |
Three different-length, mutually perpendicular axes |
Sulfur |
a ≠ b ≠ c, α = β = γ = 90° |
Trigonal |
Threefold symmetrical structure |
Quartz |
a = b = c, α = β = γ ≠ 90° |
Hexagonal |
Sixfold symmetry |
Beryl |
a = b ≠ c, α = β = 90°, γ = 120° |
Tetragonal |
Two equal lengths and one different, all perpendicular |
Rutile |
a = b ≠ c, α = β = γ = 90° |
Cubic |
Three identical, perpendicular axes |
Fluorite |
a = b = c, α = β = γ = 90° |
Triclinic |
Monoclinic |
Orthorhombic |
Trigonal/Hexagonal |
Tetragonal |
Cubic |
Image source: Wikipedia, https://en.wikipedia.org/wiki/Crystal_system
The crystal structure of a mineral affects its physical properties, such as hardness, density, and fracture characteristics. For example, cubic fluorite typically forms regular octahedral crystals, while orthorhombic olivine appears as elongated crystals. Quasicrystals, often found in metallic alloys, exhibit a quasi-periodic structure — long-range order without repeating unit cells — and can display symmetries forbidden in traditional crystals.
Miller Indices (hkl): Miller indices are a way to describe the atomic planes of a crystal in three-dimensional space. They are expressed in the form (hkl), where h, k, and l are integers that define where the plane intersects the main axes of the crystal structure.
Image source: Wikipedia, By DeepKling - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=12123337
Examples:
Miller indices are widely used in crystallography and mineral analysis, especially in X-ray diffraction (XRD), as they help to identify the structural planes of the crystal accurately.
Mineral Occurrence Forms: Minerals can appear in nature in different forms:
Additionally, minerals can be amorphous, lacking a regular crystal structure. Examples of amorphous minerals include opals and volcanic glass.
Minerals are classified based on their chemical composition into the following groups:
Mineral Group |
Structural Unit / Formula |
Well-Known Minerals |
Typical Applications |
Silicates |
[SiO₄]⁴⁻ tetrahedrons |
Quartz, Feldspar, Mica |
Glass, ceramics, electronics |
Oxides |
Metal + O |
Magnetite (Fe₃O₄), Hematite (Fe₂O₃) |
Steel, pigments, batteries |
Sulfides |
Metal + S |
Pyrite (FeS₂), Galena (PbS) |
Metal ores, sulfuric acid production |
Carbonates |
CO₃²⁻ |
Calcite (CaCO₃), Dolomite (CaMg(CO₃)₂) |
Cement, limestone, glass manufacturing |
Sulfates |
SO₄²⁻ |
Gypsum (CaSO₄·2H₂O) |
Construction boards, fertilizers |
Halides |
F⁻, Cl⁻ |
Fluorite (CaF₂), Halite (NaCl) |
Salt, optics |
Phosphates |
PO₄³⁻ |
Apatite (Ca₅(PO₄)₃(F,Cl,OH)) |
Fertilizers, lasers, toothpaste |
Elements |
— |
Gold (Au), Graphite (C) |
Electronics, jewelry, lubricants |
Mineral analysis is carried out using advanced methods that provide precise insights into the structural and chemical properties of minerals. Below are the primary techniques:
Synchrotron at Paul Scherrer Institute, Swiss Light Source. Picture: Linda Kortelainen
AI generated stibnite
Minerals are the foundational building blocks for many industrial applications, ranging from construction materials to advanced electronics. This white paper has presented a small exploration of mineral properties, classification, and analytical methods that allow for precise identification and application of minerals in various sectors.
Key insights from this analysis include:
The future of mineral analysis is marked by automation, cloud integration, and sustainable extraction processes that minimize environmental impact. Continued innovation in analytical technologies will further enhance mineral utilization and drive forward industrial efficiency and environmental stewardship.
To support these advancements, a stronger connection between mineral characterization and industry application should be encouraged. Bridging these two areas will not only improve analysis accuracy but also enhance decision-making in mining exploration, material manufacturing, and environmental sustainability.
The following sources were referenced throughout this white paper to provide detailed insights and validate the presented information: