Table 2 Results of SEM-EDS analysis of the samples concentrations are given as weight% (wt%) in oxide form

18-1 body

–

–

1.05

33.95

5.52

–

–

0.85

12.65

33.66

12.32

18-1 red layer

4.64

2.50

11.83

54.26

–

4.15

3.93

6.42

4.20

3.84

4.23

30-1 body

–

–

0.75

33.95

5.72

–

–

–

12.03

35.88

11.67

30-1 red layer

3.45

3.32

9.77

64.23

–

2.21

3.74

10.72

2.56

–

–

30-2 body

–

–

0.52

30.44

–

–

–

–

12.78

32.76

23.50

30-2 red layer

3.23

2.66

12.67

54.48

–

2.82

4.64

12.15

4.89

–

2.46

30-2-1

–

–

–

–

–

–

–

–

7.59

29.20

63.20

30-2-2

–

10.94

12.26

24.04

–

3.73

–

16.95

7.21

4.39

20.49

30-2-3

–

–

–

–

–

–

–

–

20.4

–

79.6

30-2-4

–

–

5.08

–

–

–

–

–

–

–

94.92

52-1 body

–

–

0.47

35.90

6.94

–

–

0.75

12.24

33.65

10.05

52-1 red layer

4.37

1.93

11.32

52.11

–

2.14

3.37

8.24

4.85

7.48

4.19

52-surface layer

–

–

2.57

4.02

–

–

10.59

–

7.63

–

75.20

52-1-1

–

–

1.67

3.98

–

1.04

9.73

–

7.33

–

76.25

52-1-2

–

–

–

96.03

–

–

–

–

3.96

–

–

52-1-3

–

–

1.41

–

–

–

3.27

–

6.57

–

88.76

52-1-4

–

–

–

–

–

–

9.74

–

6.37

–

83.89

52-1-5

–

–

0.33

2.28

–

–

0.43

94.39

2.57

–

–

239-2 body

0.74

–

0.65

33.77

–

0.25

0.10

–

11.93

35.4

17.25

239-2 red layer

5.02

2.16

10.84

56.31

2.26

2.53

3.50

5.97

3.84

7.57

–

240-2 body

–

–

2.10

35.95

0.80

–

1.15

–

27.45

25.90

6.65

240-2 red layer

3.67

2.03

14.42

56.13

–

2.04

3.67

7.08

–

9.92

1.04