常用建材的放射性 （pCi/g)

材料                            Uranium    Thorium   Potassium

Granite                         1.7             0.22           32

Sandstone                    0.2              0.19            11

Cement                        1.2             0.57           6.4

Limestone Concrete     0.8               0.23            2.4

Sandstone Concrete     0.3                0.23           10

Drywall                        0.4                0.32          2.4

Natural Gypsum          0.4                 0.2           4

Wood                            -                     -               90

Clay Brick                      3                    1.2             18

Ci是Curie的縮寫, 是放射強度的單位，相當於一克Radium的放射性。Curie是發現Radium的居裏夫人的姓。