Heavy Rare Earth Elements (HREE)

Scarce, supply-constrained, and irreplaceable — the elements that decide whether magnets survive heat.

What are HREE rare earth elements?

HREE definition: Heavy rare earth elements are the scarcer rare earth group from europium through lutetium, plus yttrium, under the classification used in this guide.

The HREE group includes europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and yttrium, with scandium often associated commercially. These elements are far scarcer in economic concentrations than the light rare earths. Most global supply has historically come from ion-adsorption clay deposits in southern China and Myanmar, making the HREE supply chain the most concentrated and strategically exposed segment of the critical minerals landscape. Dysprosium and terbium are essential additives that let permanent magnets operate at high temperature.

Defining Characteristics

  • Atomic numbers 63–71 plus yttrium (39); scandium (21) often grouped alongside
  • Boundary convention varies: some classifications start the heavies at gadolinium — here we include europium with the HREEs
  • Rarely form standalone deposits — recovered mainly from ion-adsorption clays
  • Supply heavily concentrated in southern China and Myanmar
  • Dysprosium and terbium command the highest prices in the REE basket
  • No commercial substitutes for high-temperature magnet applications

HREE vs LREE: heavy and light rare earths compared

The dividing line varies by source. This guide counts La–Sm as LREE and Eu–Lu plus Y as HREE, with scandium associated commercially with the heavy group.

A practical comparison of LREE and HREE membership, sources, supply, and magnet roles.
ComparisonLREE — light rare earth elementsHREE — heavy rare earth elements
MembersLa–Sm (atomic numbers 57–62); this guide places Eu with the HREE groupEu–Lu plus Y; scandium is often associated commercially with the HREE group
Typical sourcesMostly bastnaesite and monazite hard-rock depositsMostly ion-adsorption clays and xenotime-rich deposits
Supply profileHigher-volume and generally more abundant, with NdPr carrying much of the basket valueLower-volume, scarcer, and more geographically concentrated than LREE supply
Permanent-magnet roleNd and Pr form the base of high-strength NdFeB permanent magnetsDy and Tb preserve NdFeB magnet performance at high operating temperatures

The HREEs, element by element

Sc21ScandiumThe aerospace lightweighter that has never had a real market — yet.Y39YttriumNot a lanthanide, but produced and priced like one.Eu63EuropiumThe phosphor element that made color television — and anti-counterfeit euros — possible.Gd64GadoliniumThe MRI contrast metal with the best neutron shield in the periodic table.Tb65TerbiumGram for gram, one of the most expensive industrial metals on Earth.Dy66DysprosiumThe heat shield of the magnet world — no dysprosium, no EV traction motor.Ho67HolmiumThe most magnetic element in nature — used a few kilograms at a time.Er68ErbiumThe element quietly carrying most of the world’s internet traffic.Tm69ThuliumThe rarest stable rare earth — portable X-rays and precision surgical lasers.Yb70YtterbiumA cheap heavy rare earth doing some of the most precise work in physics.Lu71LutetiumThe rarest stable rare earth — and the last one out of the separation line.

Why the HREEs matter

A single EV traction motor magnet needs dysprosium or terbium to survive operating temperatures, and there is no Western supply chain of scale for either. HREE scarcity is the binding constraint on magnet manufacturing outside China, which is why new ionic-clay and xenotime projects — and heavy separation capacity — attract strategic investment and government backing far beyond their tonnage.

Apply the HREE marketDy/Tb Diffusion MagnetsSee how Dy/Tb grain-boundary diffusion stretches scarce HREE supply in EV and defense magnets.
Continue exploringLREE: Light Rare Earth ElementsThe high-volume workhorses of the rare earth complex — abundant, magnet-critical, and geopolitically charged.