Abundance of the naturally occurring rare-earth elements

(parts per million)

element Earth's crust average of 20 chondritic meteorites composite of 40 North American shales western North American Precambrian granites Kilauea basalt

rank* abundance

Sc 46 5.0 — — — —

Y 31 28.0 1.800 35.00 31.00 —

La 35 18.0 0.300 39.00 49.00 10.50

Ce 29 46.0 0.840 76.00 97.00 35.00

Pr 45 5.5 0.120 10.30 11.00 3.90

Nd 32 24.0 0.580 37.00 42.00 17.80

Sm 42 6.5 0.210 7.00 7.20 4.20

Eu 57 1.1 0.074 2.00 1.25 1.31

Gd 43 6.4 0.320 6.10 5.80 4.70

Tb 59 0.9 0.049 1.30 0.94 0.66

Dy 50 4.5 0.310 — — 3.00

Ho 56 1.2 0.073 1.40 1.22 0.64

Er 54 2.5 0.210 4.00 3.20 1.69

Tm 65 0.2 0.023 0.58 0.53 0.21

Yb 53 2.7 0.170 3.40 3.50 1.11

Lu 60 0.8 0.031 0.60 0.52 0.20

*Expressed in a range of 1 to 105.