Natural Science in Archaeology

2.4 Color of Minerals 33
Table 2.2 Electronic confi guration of the fi rst 36 elements (transition elements are in capital
letters; s, p, d, f are orbital designations)
Atomic Name of First Second Third Fourth
number element Symbol shell shell shell shell
s s p s p d s p d f
1 Hydrogen H 1
2 Helium He 2 Inert gas
3 Lithium Li 2 1
4 Beryllium Be 2 2
5 Boron B 2 2 1
6 Carbon C 2 2 2
7 Nitrogen N 2 2 3
8 Oxygen O 2 2 4
9 Fluorine F 2 2 5
10 Neon Ne 2 2 6 Inert gas
11 Sodium Na 2 2 6 1
12 Magnesium Mg 2 2 6 2
13 Aluminum Al 2 2 6 2 1
14 Silicon Si 2 2 6 2 2
15 Phosphorus P 2 2 6 2 3
16 Sulfur S 2 2 6 2 4
17 Chlorine Cl 2 2 6 2 5
18 Argon Ar 2 2 6 2 6 Inert gas
19 Potassium K 2 2 6 2 6 1
20 Calcium Ca 2 2 6 2 6 2
21 SCANDIUM Sc 2 2 6 2 6 1 2
22 TITANIUM Ti 2 2 6 2 6 2 2
23 VANADIUM V 2 2 6 2 6 3 2
24 CHROMIUM Cr 2 2 6 2 6 5 1
25 MANGANESE Mn 2 2 6 2 6 5 2
26 IRON Fe 2 2 6 2 6 6 2
27 COBALT Co 2 2 6 2 6 7 2
28 NICKEL Ni 2 2 6 2 6 8 2
29 COPPER Cu 2 2 6 2 6 10 1
30 Zinc Zn 2 2 6 2 6 10 2
31 Gallium Ga 2 2 6 2 6 10 2 1
32 Germanium Ge 2 2 6 2 6 10 2 2
33 Arsenic As 2 2 6 2 6 10 2 3
34 Selenium Se 2 2 6 2 6 10 2 4
35 Bromine Br 2 2 6 2 6 10 2 5
36 Krypton Kr 2 2 6 2 6 10 2 6 Inert gas
of light. A given iron ion, say ferric iron (Fe 3+ ), does not have a characteristic
color since the specific absorption will be modified by the environment of the ion.
The colors of compounds where the same ion is surrounded by a nearly identical
arrangement of other ions are quite similar. For instance, the two iron silicates
olivine, (FeMg) 2 SiO 4 , and tremolite-actinolite, Ca 2 (MgFe) 3 Si 8 O 22 (OH) 2 , are both
green since the ferrous ion (Fe 2+ ) has a similar environment. Consider also the