**2. Analysis of minerals**

#### **2.1 Mediterranean seashore sample**

A sample from the southern part of the Mediterranean seashore was observed using scanning electron microscopy (SEM). The grains consist of transparent quartz grains (SiO2) and black grains (**Figure 1**). The black grains were separated and checked using SEM and energy dispersive systems (EDS). It appears from the chemical analyses that these black grains are composed mainly of Ti-oxides.

#### **2.2 Judean Mountains samples**

Samples from the Judean Mountains in Israel were collected from layers of marl or clay. The samples were chipped or broken. The fresh surface was gold-carbonate *Minerals Observed by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy… DOI: http://dx.doi.org/10.5772/intechopen.102477*

#### **Figure 1.**

*(a) Observation under the magnifying glass of sand from the southern part of the Israeli coast had transparent quartz grains and black grains, (b) SEM image of the black grains, and (c) chemical analyses of the black grains obtained by EDS, showing clays and Ti-oxide with iron impurity.*

#### **Figure 2.**

*(a) Map of Israel with Judean mountains and the Dead Sea, and (b) SEM image of dolomite and goethite crystals from the Judean Hills in Israel.*

coated for back-scattered mode on SEM and the chemical composition was established with EDS. By observing the samples, newly-formed minerals were identified by their euhedral morphology. Crystals of dolomite (CaMg(CO3)2) were identified

#### **Figure 3.**

*SEM image of idiomorphic shape of K-feldspar on euhedral dolomite crystals in marl layers of the Judean Hills in Israel.*

in the argillaceous strata of the Judea group in the Judean Hills (**Figure 2**). The euhedral morphology indicates that they were formed in the marl layer. Goethite (FeOOH) crystals were formed later, filling the open spaces between the dolomite crystals.

In the marl layer K-feldspar, probably orthoclase or adularia (KAlSi3O8), was formed on euhedral dolomite crystals (**Figure 3**). Euhedral morphology of the K-feldspar indicates that it was formed in situ after dolomite crystallization [3]. Finding autogenic K-feldspar in the marl layers enabled measurement of the age of the layers [10].

Some of the dolomites in the Judean Hills were dissolved due to exposure to rains (**Figure 4**). The inner part was dissolved probably due to initial crystallization of dolomite with Ca/Mg > 1. As the dolomite crystallization continued, the outer part had a ratio of Ca/Mg = 1 so the dolomite was more stable. The dissolved inner part was later filled with calcite and clay minerals.

Crystallization of calcite (CaCO3) along with clay minerals formed by agglutination of cyanobacteria caused formation of a tube (**Figure 5**).

#### **Figure 4.**

*SEM image of dolomite with inner part dissolved and outer part remained stable.*

#### **Figure 5.**

*SEM image of tube morphology of calcite and clays indicates biogenic origin and formation by cyanobacteria.*

*Minerals Observed by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy… DOI: http://dx.doi.org/10.5772/intechopen.102477*

#### **2.3 Samples from Red Sea deeps**

Samples were collected from cores in the Atlantis II and Thetis Deeps from the central Red Sea [9]. The sediments there were formed in a highly saline hydrothermal environment. Magnetite (Fe3O4) crystals were studied using SEM. They crystallized in the Thetis Deep located in the central Red Sea (**Figure 6**). Needles of goethite precipitate close to the magnetite. Point analyses measured on the magnetite yielded Si/Fe = 0.01 and impurities of V with V/Fe = 0.002 and Mn with Mn/Fe = 0.002.

Foraminifera's shells that originate from the upper part of the Red Sea sink and attach to the magnetite crystals.

Nano-sized particles (5–200 nm) were checked under transmission electron microscopy (TEM) using JEOL JEM-2100f analytical TEM operated at 200 kV, equipped with a JED-2300 T energy dispersive spectrometer (EDS) for microprobe elemental analyses. All chemical analyses were obtained by point analysis with a beam width of 1 nm JEOL. Crystalline phases were identified, using selected area electron diffraction (SAED) in the TEM.

#### **Figure 6.**

*(a) Location of the Thetis deep and Atlantis II deep in the Red Sea, (b) SEM image of euhedral magnetite crystals surrounded by goethite crystals, and (c) SEM image of magnetite crystallized in the Thetis deep in the Red Sea with foraminifer's shells.*

#### **Figure 7.**

*TEM image of mono-domain goethite with twinning from the Red Sea deeps due to elevated temperature. Goethite had an impurity of Si/Fe 0.02 atomic ratio.*

#### **Figure 8.**

*(a) HRTEM image of multi-domain goethite, (b) HRTEM image of the goethite, (c) fast Fourier transformation that shows the well-crystallized goethite, and (d) TEM image of goethite with twinning forming a star shape impurity of Si/Fe 0.04 atomic ratio.*

Samples that were crystallized in the Red Sea Deeps had various morphologies due to salinity of the hydrothermal brines and their high temperature. Goethite (α-FeOOH) appears as mono-domain with twinning (**Figure 7**) or as multi-domain (**Figure 8**) and by high resolution, it is possible to observe well-crystallized phases. Impurity of Si in the goethite crystals was observed within the crystals: Si/Fe = 0.1 in multi-domain phase and Si/Fe = 0.02 in mono-domain structure. Star shape had Si/ Fe = 0.04. Crystallization of goethite occurred at the upper part of the hydrothermal brine due to iron that discharges from the Deep and oxygen from Red Sea deep water.

Tiny goethite crystals grow on groutite (αMnOOH) in a sample from the southern part of the Atlantis II Deep in the Red Sea [11]. Groutite and goethite are iso-structural; hence crystallization of goethite was favored (**Figure 9**).

**Figure 9.** *HRTEM image of goethite crystallized on groutite.*

*Minerals Observed by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy… DOI: http://dx.doi.org/10.5772/intechopen.102477*

#### **2.4 Samples from Dead Sea area and the Red Sea**

In the Dead Sea area, colored halite can be observed with iron oxides preserved within halite crystals. Samples were studied using HRTEM [12]. Multi-domain akaganéite (β-FeOOH) (**Figure 10**) and multi-domain lepidocrocite (γ-FeOOH) (**Figure 11**) were crystallized in the area of the Dead Sea and then covered by halite crystals that preserved the initial phases.

Formation of akaganéite requires the presence of Cl<sup>−</sup> ions, which had Si and Mn impurities (Si/Fe = 0.06, Mn/Fe = 0.06).

Lepidocrocite is crystallized at slow oxidation at pH > 5 and in the presence of chloride [12]. Plate morphologies of lepidocrocite were observed in Atlantis II and Discovery Deeps sediments in the Red Sea. Rod morphology was observed in sediments of the Thetis Deep in the Red Sea [9].

Formation of ferroxyhyte (δ-FeOOH) requires high oxidation conditions [13]. Ferroxyhyte was crystallized at the transition zone between the Red Sea deep water and the hydrothermal saline brine. Sample was collected from the upper part of sediments in the south-west basin of the Atlantis II Deep in the Red Sea. Ferroxyhyte

#### **Figure 10.**

*(a) Halite crystals from the Dead Sea area that include iron oxides, and (b) HRTEM image of multi-domain akaganéite (β-FeOOH) it contributes to the color of halite.*

#### **Figure 11.**

*(a) Dead Sea area close to the seashore with halite that precipitates from the lake, (b) TEM image of lepidocrocite crystals that cause the color of the halite. Lepidocrocite crystals had impurities of Si/Fe 0.06 and Mn/Fe 0.06, and (c) HRTEM image of lepidocrocite preserved in the halite crystals.*

**Figure 12.**

*(a) HRTEM image of folded layers of ferroxyhyte from the sediments of the Atlantis II deep, (b) Electron diffraction of ferroxyhyte, and (c) HRTEM image shows a well-crystallized phase without dislocations.*

appears as folded layers and a high resolution image shows that there are no dislocations in the crystals (**Figure 12**).

In the southern part of Atlantis II Deep in shallow water, Mn oxides were formed from the upper part of the brine. Minerals identified were todorokite (Ca,Mg)1−x Mn4+O12\*3−4H2O, with impurities of Si/Mn = 0.15, Fe/Mn = 0.28. Manganite γ-MnOOH had also an impurity of Si/Mn = 0.10 and Fe/Mn = 0.20 (**Figure 13**).

**Figure 13.**

*TEM images of Mn oxides from the southern part of the Atlantis II deep with Fe and Si impurities. (a) Todorokite (Ca,Mg)1−xMn4+O12\*3−4H2O, and (b) manganite γ-MnOOH, with electron diffraction.*

*Minerals Observed by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy… DOI: http://dx.doi.org/10.5772/intechopen.102477*

Similar phases were also identified in the Chain and Discovery Deeps close to the Atlantis II Deep in the Red Sea [11].

#### **2.5 Samples from the coastal plain of Israel**

Quartz grains are dominant in soils on the coastal plain of Israel. Clay minerals, kaolinite (Al2Si2O5(OH)4), montmorillonite ((Al2Mg3)Si4)10(OH)2nH2O), which arrive in the area as dust storms, cover the well rounded quartz grains. Iron oxides, mainly hematite (Fe2O3) crystals, are attached to the clay minerals and contribute to the red color of the red sandy soils (**Figure 14**).

#### **2.6 Dust samples of Israel**

Dust storms are common in Israel, (**Figure 15**). Dust samples were collected and studied with TEM. Most of the samples contain clay minerals, mainly montmorillonite, kaolinite and small amounts of illite. Nano-sized iron and titanium oxides are

**Figure 14.** *(a and b) TEM images of rounded quartz grains covered by kaolinite and hematite in red sandy soil.*

#### **Figure 15.**

*(a) Dust storm in the Middle East, (b) TEM image of well-crystallized rutile that was identified in the dust along with clays and hematite, and (c) HRTEM image of dust samples made of clay minerals mainly montmorillonite and kaolinite. Hematite, ilmenite and Ti oxides are attached to the clays.*

attached to the clay minerals forming clusters. The dust also covers quartz grains in sand dunes along the Mediterranean seashore and colors them into darker colors.
