## 3 Results and Discussion
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Mineral Phase**} & **Amosite** & **Amosite** & **Cracidolite** & **Cracidolite** & **[PERSON] et al.** & **Tremolite** & **Tremolite** \\  & **This Work** & **2004 [26]** & **This Work** & **2004 [26]** & **This Work** & **2004 [26]** \\ \hline  & 156 & 155 & 109 & & 162 & 162 \\  & 184 & 182 & 134 & & 180 & 180 \\  & 215 & 216 & 147 & & & 225 \\  & & 252 & 166 & 162 & 234 & 234 \\  & & 289 & 197 & 195 & 252 & 254 \\  & & 307 & & 211 & 290 \\  & 348 & 348 & 229 & & 306 \\  & 368 & 368 & 252 & 246 & 335 \\  & 400 & 400 & 274 & 272 & 348 \\  & 423 & 423 & 300 & 300 & 354 & 355 \\  & & 507 & 335 & 331 & 372 & 373 \\ Mineral Raman Bands & 528 & 528 & 365 & 360 & 396 & 396 \\ (cm\({}^{-1}\)) & 660 & 659 & 377 & 374 & 418 & 418 \\  & 904 & 433 & 428 & 438 & 438 \\  & 970 & 968 & 472 & 470 & 516 & 516 \\  & 1021 & 1020 & 510 & 506 & 531 & 531 \\  & & 1093 & 542 & 537 & 676 & 676 \\  & & & 580 & 577 & 738 & 740 \\  & & & 666 & 664 & 750 & 751 \\  & & & & 733 & 931 & 932 \\  & & & & 771 & 952 & 950 \\  & & & 891 & 889 & 1031 & 1031 \\  & & & 971 & 967 & 1062 & 1062 \\  & & & 1030 & & & \\  & & & 1089 & 1082 & & \\ \hline  & 1332 & & 1333 & & - & \\  & & & 1470 & & - & \\ CM Raman Bands & 1582 & & 1591 & n.a. & - & n.a. \\ (cm\({}^{-1}\)) & 2663 & & 1621 & & - & \\  & 2663 & & 2660 & & - & \\  & & 2914 & & - & \\ \hline OH- Raman Bands & 3618 & n.a. & - & n.a. & - & n.a. \\ (cm\({}^{-1}\)) & 3637 & n.a. & - & n.a. & - & n.a. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Raman bands observed on the mineral phases defined “asbestos” by the Law. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Mineral Phase**} & **Anthophyllline** & **Anthophyllline** & **Actimolite** & **Chrysotile** & **[PERSON] et al. ** \\  & **This Work** & **2004 [26]** & **This Work** & **This Work** & **2003 [130]** \\ \hline  & 188 & 188 & 118 & 132 & \\  & 222 & 149 & 203 & \\  & 254 & 254 & 175 & 234 & 231 \\  & 265 & 265 & 221 & 347 & 345 \\  & 304 & 304 & 386 & 390 & 389 \\  & 342 & 342 & 532 & 432 & \\Considering now the erionite samples, the spectral range where lie the lattice vibrational modes appeared poorer in Raman bands. In fact, only an intense band at about 485 cm\({}^{-1}\), with an evident component at about 470 cm\({}^{-1}\), and weaker bands at about 570, 330-345, and 127-140 cm\({}^{-1}\) characterized the Raman spectrum, Figure 5.  
Nevertheless, all the studied erionite fibers exhibited, under SEM, particles, sub-micrometric in size, lying on the crystal surface, Figure 6.  
Directing the laser beam onto the observed grains, different results were obtained on erionite from the various outcrops. In particular on the erionite from Oregon, the Raman spectra recorded on the grains identified:  
* Goethite, chemical formula FeO(OH), Raman spectra as that shown in Figure 7a. In this case the band at 395 cm\({}^{-1}\) resulted, with respect to the value, 385 cm\({}^{-1}\), normally observed on this mineral, shifted of 10 cm\({}^{-1}\) as consequence of a poor crystallinity of the grains [33; 34];
* Hematite, chemical formula Fe\({}_{2}\)O\({}_{3}\), spectra as that shown in Figure 7b [34; 35];
* Jarosite, KFe\({}_{3}\)\({}^{+}\)(SO\({}_{4}\))\({}_{2}\)(OH)\({}_{6}\), an iron-potassium sulphate [35; 36], Figure 7c. On the Raman spectrum recorded on the grains of jarosite, the presence of a band at 387 cm\({}^{-1}\), not ascribing to this mineral phase, indicated a contemporaneous crystallization of small amounts of goethite [34; 35]. Figure 5: Raman spectra in the 1200–100 cm\({}^{-1}\) range obtained on erionite from (**a**) Oregon, (**b**) Karlik, and (**c**) North Dakota. Figure 6: Backscattered scanning electron microscopy (SEM) images of erionite fibers from (**a**) Oregon, (**b**) Karlik, and (**c**) North Dakota. The arrows indicate particles lying on the crystal surfaces. Therefore, the described results indicated many iron particles lying on the surface of the erionite fibers.