REE Pattern (Rare Earth Element Pattern)
Definition
A plot of rare earth element concentrations normalised to chondrite or primitive mantle, showing the relative enrichment or depletion of each REE from La to Lu. REE patterns are controlled by the mineralogy of the host rock and the chemistry of crystallising fluids, making them distinctive fingerprints for deposit type and geographic origin.
- Elements plotted
- Lanthanum (La) through Lutetium (Lu)
- Normalised to
- Chondrite or primitive mantle values
- Controlled by
- Host rock mineralogy and crystallising fluid chemistry
- Application
- Distinguishing gem or mineral deposit type and geographic origin
Common questions
What does a europium anomaly on an REE pattern indicate?+
A negative europium dip usually signals feldspar fractionation in the source melt, since feldspar preferentially incorporates europium over the other rare earths. This kind of anomaly is one of the diagnostic shape features examiners read off the plot to narrow deposit type.
Is an REE pattern enough on its own to prove a gem's origin?+
Rarely. REE patterns are one line of evidence among several, typically combined with trace element ratios, inclusion mineralogy, and isotope data, because deposits from different regions can produce broadly similar pattern shapes.
Related terms
- Conflict Mineral
- A mineral whose extraction or trade finances armed conflict. The OECD defines 3TG (tin, tantalum, tungsten, gold) from conflict-affected and high-risk areas...
- Epsilon-Nd (εNd)
- The 143Nd/144Nd ratio of a sample expressed as a deviation in parts per ten thousand from the chondritic uniform reservoir (CHUR). Positive...
- Inclusion Fingerprinting
- Identification of mineral inclusions trapped inside a gemstone during growth as indicators of the geological environment. Marble-hosted rubies typically contain calcite and...
- Kimberley Process (KPCS)
- An international certification scheme launched in 2003 that requires participant countries to certify that rough diamonds are conflict-free before export. Isotope and...
- LA-ICP-MS Trace-Element Profiling
- Laser ablation inductively coupled plasma mass spectrometry applied directly to a polished gemstone surface. It measures dozens of trace elements simultaneously in...