This page covers how the discipline and its testing methods developed; material entries do not repeat it. It does not give a discovery history for each material: authoritative sources say little about when individual materials were first found or described, and most of what they do say is about naming (already in each entry's name origin). That is an honest statement of where the sources stop, not an omission.
The short answer
Gemmology is not an ancient discipline — it became technical only in the 20th century, moving from the loupe and refractometer to spectroscopy, X-ray imaging and trace-element analysis. What can be measured decides what can be known.
Where the technical turn began
- Earlier roots: in the early 1900s, Herbert Smith at the British Museum in London promoted the optical refractometer for gem testing (his account was published in 1907); he and his contemporaries also discussed practical tests such as dichroism, absorption spectra, density and hardness.
- GIA's start: GIA was founded in 1931 and began testing gems with scientific instruments a few years later; by the late 1930s it was evaluating basic instruments — loupe, microscope, hand spectroscope, refractometer, dichroscope — and teaching how to use them properly.
- Its own equipment: in 1938 GIA introduced a commercially available stereomicroscope with darkfield illumination, which gave a better view of inclusions and clarity features.
Basis: the historical overview in GIA's Gems & Gemology, Winter 2024 (see sources at the end).
Steps driven by demand
This table scrolls sideways on narrow screens.
| When | What happened | Why it mattered |
|---|---|---|
| 1949 | The GIA Gem Trade Laboratory opened in New York | Testing for trade clients became routine, and so did instrument use |
| 1955 | GIA issued its first diamond grading reports (see quality grading and value factors) | Grading reports became a system, and instrument testing increased further |
| 1976 | GIA created its research department and acquired its first scanning electron microscope | The adoption of advanced scientific instruments accelerated |
Basis: as above.
Who does what among today's instruments
A modern gemmological laboratory divides its capabilities by the question each method answers:
This table scrolls sideways on narrow screens.
| Instrument / method | What it mainly answers |
|---|---|
| Magnification and microscopy | Inclusions, growth features, signs of treatment — the most basic source of evidence |
| Refractometer / polariscope | Refractive index and optical character, to identify the mineral species |
| UV–visible spectroscopy | Colouring ions and colour centres (the cause of colour) |
| Infrared / Raman spectroscopy | Molecular groups, water content and organic fillers |
| XRF and LA-ICP-MS | Trace-element composition — to separate natural from synthetic and to support origin determination |
| X-ray radiography and micro-CT | Internal structure (nacre in pearl, assembled structures, distribution of fillers) |
Basis: two articles in GIA's Gems & Gemology, Winter 2024 — on chemical analysis by XRF and LA-ICP-MS, and on X-ray radiography and computed microtomography (see sources at the end).
Why this history matters to readers
- It explains why testing is needed: many criteria (trace elements, internal structure) are invisible to the eye and the loupe; they need instruments.
- It explains why conclusions change: new instruments bring new criteria, and older conclusions can be revised — identification conclusions belong to their time.
- It builds trust: it shows we understand the chain from instrument to conclusion, rather than treating sources as slogans.
Conclusion of this page
Modern gem identification rests on instrumental testing (spectroscopy, X-ray imaging, trace-element analysis); many criteria are unreachable by eye or by name, and the field's understanding is revised as techniques advance, so conclusions must be issued by a qualified laboratory for a specific specimen. Laboratory testing and report wording lists the tests the CIBJO protocol requires and how reports word their findings.