Every material has two important sides to its identity: what it contains and how those constituents are arranged.
The first is its material composition. It describes the elements or chemical constituents present and, where required, their quantities. A steel alloy, for example, may contain iron together with controlled amounts of carbon, chromium, nickel and other elements. Changes in these concentrations can mean that the material no longer matches the intended grade.
The second is its material structure. This looks beyond the list of elements and examines how the material exists internally. In crystalline materials, atoms are arranged in defined patterns that form different phases. Two samples can therefore contain similar elements but have different structures or phases and those differences can influence their properties and behaviour.
This distinction is central to material characterization. Finding an element does not always explain the form in which it occurs, while identifying a crystalline phase does not necessarily provide the complete elemental composition.
Why Composition and Structure Need to Be Understood Separately
Material investigations usually begin because something needs to be confirmed.
A manufacturer may need to verify whether an incoming metal is actually the specified alloy. A cement laboratory may need to check the chemistry of a raw material. A mining laboratory may know which elements occur in an ore but still need to identify the minerals containing them.
These situations require different information.
Composition Tells Us What the Material Contains
Composition analysis reveals the elements present in a sample and, depending on the method, their concentrations.
This information supports areas such as:
- Raw-material chemistry checks
- Alloy composition verification
- Production-material monitoring
- Investigation of unexpected elemental content
- Chemical specification checks
X-ray fluorescence (XRF) and optical emission spectrometry (OES) are established techniques for elemental analysis, although their applications and sample requirements differ.
Structure Shows the Form of the Material
Elemental information does not always provide a complete description of a sample.
In crystalline materials, elements can occur within different phases. These phases can influence properties and may change as a result of processing, temperature, raw-material variation or other conditions.
X-ray diffraction (XRD) is used to investigate this structural information by analysing the diffraction pattern produced by crystalline material.
In simple terms, composition identifies what the material contains, while structural analysis provides information about the crystalline form in which those constituents occur.
Practical Situations Where Different Information Is Needed
The distinction becomes clearer when composition and structure are applied to actual material problems.
Case 1: Similar Metal Parts Show Different Processing Behaviour
A production facility receives metal components from two batches. Their appearance and dimensions are similar, but one batch behaves differently during subsequent processing.
Chemical verification can help determine whether variation in the alloy composition is contributing to the difference.
Spark optical emission spectrometry measures the elemental composition of solid metals and alloys. The Thermo Scientific ARL iSpark Plus is an example of an OES spectrometer used for this type of metal analysis.
Differences in alloying or trace-element concentrations can therefore be identified even when the components appear physically similar.
The analysis provides evidence that can help separate a material-composition issue from other possible causes within the production process.
Case 2: Raw Material Requires Chemical Verification Before Processing
A cement or mineral-processing facility receives a new raw-material batch. Before the material enters production, its chemistry needs to be checked against established requirements.
An XRF spectrometer can determine the elemental composition of the sample. The Thermo Scientific ARL X900 is an example of a WDXRF spectrometer used for elemental analysis across materials such as cement, minerals and metals.
The resulting XRF elemental analysis can identify variations in relevant elemental concentrations before the raw material moves further through the process.
Where chemical composition is the main concern, this information may be sufficient without extending the investigation into crystal structure.
Case 3: Elemental Results Do Not Fully Identify a Mineral
A mineral sample has already undergone elemental analysis. The results confirm the presence of iron, oxygen and other constituents, but they do not establish the specific iron-bearing mineral phases within the sample.
The missing information is structural.
Different crystalline phases can contain similar elements while representing different mineral forms. An X-ray diffractometer can distinguish these phases from their characteristic diffraction patterns.
The ARL X’TRA Companion is an example of a benchtop XRD system used for phase analysis and material characterization.
In this situation, XRD phase analysis adds information that elemental measurement cannot provide on its own.
Case 4: Chemical and Mineral Information Are Both Relevant
A mining laboratory may need a broader understanding of an ore sample.
XRF analysis can establish its elemental composition, including elements such as iron, silicon and aluminium. However, processing decisions may also depend on the minerals associated with those elements.
XRD can then support mineral phase identification.
The two measurements provide complementary information. One establishes the chemical constituents, while the other identifies crystalline mineral phases. Together, they create a more complete description of the sample without duplicating the same analysis.
Build the Analysis Around the Material Problem
There is no single measurement that automatically provides every useful piece of information about a material.
For solid metals and alloys, OES can support detailed chemical verification.
For cement, minerals and other industrial materials where elemental composition is important, XRF provides a route to chemical characterization.
Where crystalline phases or structural identity need to be established, XRD material analysis provides another level of information.
In more complex investigations, chemical and structural measurements can be combined. The value comes from using each technique for a distinct purpose rather than performing additional analysis without a defined need.
A Practical Basis for Selecting the Analysis
Selection can be guided by three main factors: sample type, missing information and purpose of the investigation.
A solid metal requiring alloy verification points toward OES. A raw material requiring elemental concentrations may be suited to XRF. A crystalline material requiring phase identification calls for XRD.
When both chemical composition and crystalline identity influence the investigation, complementary methods can be used to build a broader material profile.
This approach keeps the analytical process connected to the actual material problem rather than to the number of instruments available.
Material Composition and Structure in the ARABLAB Context
Material characterization is one of the laboratory areas represented at ARABLAB Dubai 2026, taking place from 26–28 October 2026 at Dubai World Trade Centre.
Technologies related to the approaches discussed in this guide include the ARL X900 for XRF analysis, ARL iSpark Plus for optical emission analysis and ARL X’TRA Companion for X-ray diffraction. Information on these technologies is available through Business Communications LLC at Sheikh Saeed Hall 1, Stand SSH1-B40 during the event.
The three technologies demonstrate how different analytical principles can contribute different information to material characterization.
Building a More Complete Understanding of a Material
Material composition and material structure are closely connected, but they describe different characteristics.
Composition establishes the chemical constituents of a sample. Structural analysis adds information about crystalline phases and their arrangement. Depending on the application, either type of information may be sufficient, while more complex investigations can require both.
A metal with an uncertain grade, a raw material with unexpected chemistry and a mineral with an unidentified phase therefore require different analytical paths.
The most useful analysis is the one that addresses the missing information directly. By separating composition from structure first, laboratories can apply XRF, OES and XRD where each technique contributes meaningful information to the overall understanding of the material.
