Solid State Physics

XRD and XRF are highly complementary

materials analysis methods which, when used

together, greatly improve the accuracy of

phase identification and quantitative analysis.

The combination of both methods provides an

increase in the numbers of measured parameters,

which means that fewer assumptions are needed

for analysis. This in turn provides not only greater

accuracy of results, but also increases the range

of samples that can be measured to include

samples about which little or nothing is known in

advance.

XRD is the most direct and accurate analytical

method for determining the presence and

absolute amounts of mineral species in a sample.

Ambiguous results may be obtained however, if

the sample chemistry and/or origin are unknown.

In these cases phase identification can be difficult;

in particular, isostructural phases with similar

chemical composition will give similar powder

diffraction patterns.

In contrast to XRD, XRF provides highly accurate

information about the elemental composition

of a sample, but it cannot deliver direct phase

information. Mass-balance calculations may give

sufficient phase information in some cases, but

can also lead to meaningless results e.g. in the

presence of polymorphs.

It is the complimentary nature of the XRD and

XRFmethods which makes them a valuable

tool for quantitative phase analysis in numerous

applications ranging from scientific research

to industrial high-throughput quality control.

Particularily in mineralogical and geological

application areas, the combined use of XRD and

XRF is booming, offering completely new insights

into materials and processes. Typical examples

are the cement, minerals & mining, and industrial

minerals industries, where the quality of products

and / or efficiency of processes is governed by

both phase and elemental composition. The

combined use of XRD and XRF methods allows

the reliable analysis of materials, for which the

individual methods fail to deliver accurate and

reliable results.

Page 2

Quantitative phase and element analysis of

host/waste rocks and tailings is an important

application in the minerals and mining industry

with respect to both process optimization (e.g.

acid leaching) and environmental protection:

Mining and milling operations are responsible

for the production of billions of tonnes of waste

rock and finely crushed tailings worldwide. An

important application is the knowledge of the

relative amounts of the minerals with acid-

producing or neutralization potential for successful

acid-base accounting with respect to both the

leaching process as well as acid mine drainage,

with its detrimental effects on environment.

As an example, we report combined XRD-XRF

analysis of an intrusive rock with unknown

composition. Of particular interest was its

classification by mineral content as well as

the detection and accurate quantification of

potentially present minerals with significant acid-

producing or neutralization potential.

Powder diffraction data were recorded using a

D4 ENDEAVOR powder diffractometer equipped

with a LynxEye

TM

detector (Fig. 1); the total

measurement time required was about 5 minutes.

For phase identification and quantification,

the DIFFRAC

plus

software packages EVA,

SEARCH and TOPAS were used. Standardless

XRFmeasurements on the same sample were

performed with the S4 PIONEER and the

SPECTRA

plus

software (Fig. 1).

Fig. 1: D4 ENDEAVOR diffractometer (right)

and S4 PIONEER spectrometer (left) connected

with conveyer belt. The D4 is equipped with

Super Speed LynxEye

TM

detector.

Fig. 2: EVA phase identification results.

1) Phase identification

Fig. 2 and Tab. 1 show the XRD powder data and

the phase identification results. The major rock

forming minerals plagioclase, quartz, diopside

and muscovite are easily and correctly identified

in a single default run. Note, that the highly

sensitive SEARCH algorithm clearly prefers albite

(Na-plagioclase) versus anorthite (Ca-plagioclase)

as a result of the slightly different lattice

parameters of both plagioclase solid solution

end members. Best SEARCH figure-of-merits

obtained for the individual phases were 0.65 and

1.48, respectively. Neither ore minerals nor any

K-feldspars or feldspathoids could be detected.

Tab. 1: EVA phase identification results.

SS-VVV-PPPP

Compound Name

00-009-0466 (*)

Albite

00-041-1480 (I)

Albite, calcian

03-065-0466 (C)

Quartz low, syn

01-087-0700 (C)

Diopside, syn

01-089-5402 (C)

Muscovite 2M1

Page 3

Fig. 3: EVA combined XRD-XRF results -

comparison of calculated (column "SQD") versus

observed (column "XRF") element concentrations.

The difference is given in column "Delta".

2) Combined XRD-XRF analysis

To confirm the phase identification results,

and to obtain semi-quantitative phase amount

estimates consistent with the actual elemental

composition of the sample, combined XRD-XRF

analysis has been performed with EVA. EVA

enables semi-quantitative analysis based on the

reference-intensity-ratio (RIR) method using both

XRD as well as XRFdata simultaneously: On

scaling the maximum intensities of the ICDD PDF

patterns to the observed peaks in the powder

pattern, EVA calculates both phase and element

concentrations, and compares the latter with the

actually measured element concentrations.

Element concentrations as obtained by XRF and

used by EVA are provided in Tab. 2. Already at

first glance, the XRF data fully confirm the absence

of any significant acid-producing ore minerals

due to the minor concentrations found for heavy

elements and the absence of sulphur.

Tab. 2: Element concentrations [%] as obtained by XRF.

Oxygen

47.7

Silicon

30.0

Aluminum 9.75

Sodium

6.1

Calcium

3.66

Magnesium 0.456

Iron

1.35

Potassium

0.271

Phosphorus 0.114

Chlorine

0.0445

Titanium

0.252

Manganese 0.0173

Cobalt

0.0182

Nickel

0.0142

Strontium

0.0595

Zirconium

0.0143

Barium

0.0258

Wolfram

0.101

The results for combined XRD-XRF analysis with

EVA are shown in Fig. 3 and Tab. 3. The high Na

vs. Ca concentrations confirm the presence of Na-

plagioclase as found by XRD (diopside accounts

for about 60% of the total Ca, as calculated

by EVA). The present Na-plagioclase is most

successfully modelled using two albite phases

with different Ca amounts. Note the excellent

agreement found between the calculated and

observed element concentrations, which is better

than 1% for all elements, and therefore confirms

the correctness of the XRD phase identification

results for all phases.

The accuracy of the RIR method is limited by

several factors such as preferred orientation

effects and the quality of the ICDD PDF data used

(e.g. quality of relative intensities, I/Icor values,

idealized chemical formula).

Tab. 3: EVA semi-quantitative phase analysis

results based on combined XRD-XRF using

reference intensities as given in the ICDD PDF

patterns.

SS-VVV-PPPP

Compound Name

Phase

amounts

00-009-0466 (*)

Albite

58.2%

00-041-1480 (I)

Albite, calcian

15.4%

03-065-0466 (C) Quartz low, syn

14.0%

01-087-0700 (C) Diopside, syn

9.9%

01-089-5402 (C) Muscovite 2M1

2.6%

The most accurate quantitative results will be

obtained from a TOPAS Rietveld refinement. The

combined XRD-XRF results obtained are of high

value for defining the refinement model.

Page 4

BRUKER AXS, INC.

5465 EAST ChERYL pARKwAY

MADISON, wI 53711-5373

USA

TEL. (+1) (800) 234-XRAY

TEL. (+1) (608) 276-3000

FAX (+1) (608) 276-3006

EMAIL info@bruker-axs.com

www.bruker-axs.com

All configurations and specifications are subject to change without notice. Order No. L88-E00058. © 2006 BRUKER AXS GmbH. Printed in Germany.

BRUKER AXS GMBh

OESTLIChE RhEINBRUECKENSTR. 49

D-76187 KARLSRUhE

GERMANY

TEL. (+49) (0)(721)595-2888

FAX (+49) (0)(721)595-4587

EMAIL info@bruker-axs.de

www.bruker-axs.de

BRUKER AXS K.K

3-9-A, MORIYA, KANAGAwA

YOKOhAMA, KANAGAwA 221-0022

JApAN

TEL. (+81) 45 453 1963

FAX (+81) 45 440 0757

www.bruker-axs.com

3) Quantitative TOPAS refinement

Quantitative Rietveld analysis has been

performed using TOPAS, the results are shown

in Fig. 4 and Tab. 4. For the final refinement

two Na-plagioclases with different compositions

have been used to model the data to take the

elemental analysis results into account: Albite (0%

Ca) and Oligoclase (25% Ca).

From the results in Tab. 4 the following

conclusions can be drawn:

1. The sample can be unambiguously classified as

a quartzdiorite according to Streckeisen, see Fig. 5.

2. Combined XRD-XRF analysis and TOPAS

Rietveld refinement can allow a distinction of even

neighboring plagioclase solid solution members

(here albite and oligoclase) if present in sufficient

amounts.

The present sample can be characterised as

a rock with insignificant acid producing or

neutralisation potential. Remarkable is the easy

and reliable determination of the plagioclase type

for estimation of the neutralisation potential. This

ability is of particular interest, as anorthite has

an about 14x higher neutralisation potential than

albite (e.g. Jambor et al., 2002).

Fig. 4: Quantitative TOPAS refinement results.

Tab. 4: Quantitative TOPAS refinement results.

Compound Name

Phase amounts

Albite

49.6%

Oligoclase

30.5%

Quartz

9.9%

Diopside

8.8%

Muscovite

1.2%

Fig. 5: Streckeisen diagram for intrusive rocks.

Q: quartz, A: alkali-feldspar, P: plagioclase.

Reference

J.L. Jambor, J.E. Dutrizac, L.A. Groat, M. Raudsepp.

Environmental Geology (2002) 43, 1-17.

Q

A

P

granite

grano-

diorite

quartz-rich

granodiorite

quartz-

syenite

quartz-

monzonite

quartz-

monzo-

diorite

quartz-

diorite

tonalite

XRD and XRF are highly complementary

materials analysis methods which, when used

together, greatly improve the accuracy of

phase identification and quantitative analysis.

The combination of both methods provides an

increase in the numbers of measured parameters,

which means that fewer assumptions are needed

for analysis. This in turn provides not only greater

accuracy of results, but also increases the range

of samples that can be measured to include

samples about which little or nothing is known in

advance.

XRD is the most direct and accurate analytical

method for determining the presence and

absolute amounts of mineral species in a sample.

Ambiguous results may be obtained however, if

the sample chemistry and/or origin are unknown.

In these cases phase identification can be difficult;

in particular, isostructural phases with similar

chemical composition will give similar powder

diffraction patterns.

In contrast to XRD, XRF provides highly accurate

information about the elemental composition

of a sample, but it cannot deliver direct phase

information. Mass-balance calculations may give

sufficient phase information in some cases, but

can also lead to meaningless results e.g. in the

presence of polymorphs.

It is the complimentary nature of the XRD and

XRFmethods which makes them a valuable

tool for quantitative phase analysis in numerous

applications ranging from scientific research

to industrial high-throughput quality control.

Particularily in mineralogical and geological

application areas, the combined use of XRD and

XRF is booming, offering completely new insights

into materials and processes. Typical examples

are the cement, minerals & mining, and industrial

minerals industries, where the quality of products

and / or efficiency of processes is governed by

both phase and elemental composition. The

combined use of XRD and XRF methods allows

the reliable analysis of materials, for which the

individual methods fail to deliver accurate and

reliable results.

Page 2

Quantitative phase and element analysis of

host/waste rocks and tailings is an important

application in the minerals and mining industry

with respect to both process optimization (e.g.

acid leaching) and environmental protection:

Mining and milling operations are responsible

for the production of billions of tonnes of waste

rock and finely crushed tailings worldwide. An

important application is the knowledge of the

relative amounts of the minerals with acid-

producing or neutralization potential for successful

acid-base accounting with respect to both the

leaching process as well as acid mine drainage,

with its detrimental effects on environment.

As an example, we report combined XRD-XRF

analysis of an intrusive rock with unknown

composition. Of particular interest was its

classification by mineral content as well as

the detection and accurate quantification of

potentially present minerals with significant acid-

producing or neutralization potential.

Powder diffraction data were recorded using a

D4 ENDEAVOR powder diffractometer equipped

with a LynxEye

TM

detector (Fig. 1); the total

measurement time required was about 5 minutes.

For phase identification and quantification,

the DIFFRAC

plus

software packages EVA,

SEARCH and TOPAS were used. Standardless

XRFmeasurements on the same sample were

performed with the S4 PIONEER and the

SPECTRA

plus

software (Fig. 1).

Fig. 1: D4 ENDEAVOR diffractometer (right)

and S4 PIONEER spectrometer (left) connected

with conveyer belt. The D4 is equipped with

Super Speed LynxEye

TM

detector.

Fig. 2: EVA phase identification results.

1) Phase identification

Fig. 2 and Tab. 1 show the XRD powder data and

the phase identification results. The major rock

forming minerals plagioclase, quartz, diopside

and muscovite are easily and correctly identified

in a single default run. Note, that the highly

sensitive SEARCH algorithm clearly prefers albite

(Na-plagioclase) versus anorthite (Ca-plagioclase)

as a result of the slightly different lattice

parameters of both plagioclase solid solution

end members. Best SEARCH figure-of-merits

obtained for the individual phases were 0.65 and

1.48, respectively. Neither ore minerals nor any

K-feldspars or feldspathoids could be detected.

Tab. 1: EVA phase identification results.

SS-VVV-PPPP

Compound Name

00-009-0466 (*)

Albite

00-041-1480 (I)

Albite, calcian

03-065-0466 (C)

Quartz low, syn

01-087-0700 (C)

Diopside, syn

01-089-5402 (C)

Muscovite 2M1

Page 3

Fig. 3: EVA combined XRD-XRF results -

comparison of calculated (column "SQD") versus

observed (column "XRF") element concentrations.

The difference is given in column "Delta".

2) Combined XRD-XRF analysis

To confirm the phase identification results,

and to obtain semi-quantitative phase amount

estimates consistent with the actual elemental

composition of the sample, combined XRD-XRF

analysis has been performed with EVA. EVA

enables semi-quantitative analysis based on the

reference-intensity-ratio (RIR) method using both

XRD as well as XRFdata simultaneously: On

scaling the maximum intensities of the ICDD PDF

patterns to the observed peaks in the powder

pattern, EVA calculates both phase and element

concentrations, and compares the latter with the

actually measured element concentrations.

Element concentrations as obtained by XRF and

used by EVA are provided in Tab. 2. Already at

first glance, the XRF data fully confirm the absence

of any significant acid-producing ore minerals

due to the minor concentrations found for heavy

elements and the absence of sulphur.

Tab. 2: Element concentrations [%] as obtained by XRF.

Oxygen

47.7

Silicon

30.0

Aluminum 9.75

Sodium

6.1

Calcium

3.66

Magnesium 0.456

Iron

1.35

Potassium

0.271

Phosphorus 0.114

Chlorine

0.0445

Titanium

0.252

Manganese 0.0173

Cobalt

0.0182

Nickel

0.0142

Strontium

0.0595

Zirconium

0.0143

Barium

0.0258

Wolfram

0.101

The results for combined XRD-XRF analysis with

EVA are shown in Fig. 3 and Tab. 3. The high Na

vs. Ca concentrations confirm the presence of Na-

plagioclase as found by XRD (diopside accounts

for about 60% of the total Ca, as calculated

by EVA). The present Na-plagioclase is most

successfully modelled using two albite phases

with different Ca amounts. Note the excellent

agreement found between the calculated and

observed element concentrations, which is better

than 1% for all elements, and therefore confirms

the correctness of the XRD phase identification

results for all phases.

The accuracy of the RIR method is limited by

several factors such as preferred orientation

effects and the quality of the ICDD PDF data used

(e.g. quality of relative intensities, I/Icor values,

idealized chemical formula).

Tab. 3: EVA semi-quantitative phase analysis

results based on combined XRD-XRF using

reference intensities as given in the ICDD PDF

patterns.

SS-VVV-PPPP

Compound Name

Phase

amounts

00-009-0466 (*)

Albite

58.2%

00-041-1480 (I)

Albite, calcian

15.4%

03-065-0466 (C) Quartz low, syn

14.0%

01-087-0700 (C) Diopside, syn

9.9%

01-089-5402 (C) Muscovite 2M1

2.6%

The most accurate quantitative results will be

obtained from a TOPAS Rietveld refinement. The

combined XRD-XRF results obtained are of high

value for defining the refinement model.

Page 4

BRUKER AXS, INC.

5465 EAST ChERYL pARKwAY

MADISON, wI 53711-5373

USA

TEL. (+1) (800) 234-XRAY

TEL. (+1) (608) 276-3000

FAX (+1) (608) 276-3006

EMAIL info@bruker-axs.com

www.bruker-axs.com

All configurations and specifications are subject to change without notice. Order No. L88-E00058. © 2006 BRUKER AXS GmbH. Printed in Germany.

BRUKER AXS GMBh

OESTLIChE RhEINBRUECKENSTR. 49

D-76187 KARLSRUhE

GERMANY

TEL. (+49) (0)(721)595-2888

FAX (+49) (0)(721)595-4587

EMAIL info@bruker-axs.de

www.bruker-axs.de

BRUKER AXS K.K

3-9-A, MORIYA, KANAGAwA

YOKOhAMA, KANAGAwA 221-0022

JApAN

TEL. (+81) 45 453 1963

FAX (+81) 45 440 0757

www.bruker-axs.com

3) Quantitative TOPAS refinement

Quantitative Rietveld analysis has been

performed using TOPAS, the results are shown

in Fig. 4 and Tab. 4. For the final refinement

two Na-plagioclases with different compositions

have been used to model the data to take the

elemental analysis results into account: Albite (0%

Ca) and Oligoclase (25% Ca).

From the results in Tab. 4 the following

conclusions can be drawn:

1. The sample can be unambiguously classified as

a quartzdiorite according to Streckeisen, see Fig. 5.

2. Combined XRD-XRF analysis and TOPAS

Rietveld refinement can allow a distinction of even

neighboring plagioclase solid solution members

(here albite and oligoclase) if present in sufficient

amounts.

The present sample can be characterised as

a rock with insignificant acid producing or

neutralisation potential. Remarkable is the easy

and reliable determination of the plagioclase type

for estimation of the neutralisation potential. This

ability is of particular interest, as anorthite has

an about 14x higher neutralisation potential than

albite (e.g. Jambor et al., 2002).

Fig. 4: Quantitative TOPAS refinement results.

Tab. 4: Quantitative TOPAS refinement results.

Compound Name

Phase amounts

Albite

49.6%

Oligoclase

30.5%

Quartz

9.9%

Diopside

8.8%

Muscovite

1.2%

Fig. 5: Streckeisen diagram for intrusive rocks.

Q: quartz, A: alkali-feldspar, P: plagioclase.

Reference

J.L. Jambor, J.E. Dutrizac, L.A. Groat, M. Raudsepp.

Environmental Geology (2002) 43, 1-17.

Q

A

P

granite

grano-

diorite

quartz-rich

granodiorite

quartz-

syenite

quartz-

monzonite

quartz-

monzo-

diorite

quartz-

diorite

tonalite

XRD and XRF are highly complementary

materials analysis methods which, when used

together, greatly improve the accuracy of

phase identification and quantitative analysis.

The combination of both methods provides an

increase in the numbers of measured parameters,

which means that fewer assumptions are needed

for analysis. This in turn provides not only greater

accuracy of results, but also increases the range

of samples that can be measured to include

samples about which little or nothing is known in

advance.

XRD is the most direct and accurate analytical

method for determining the presence and

absolute amounts of mineral species in a sample.

Ambiguous results may be obtained however, if

the sample chemistry and/or origin are unknown.

In these cases phase identification can be difficult;

in particular, isostructural phases with similar

chemical composition will give similar powder

diffraction patterns.

In contrast to XRD, XRF provides highly accurate

information about the elemental composition

of a sample, but it cannot deliver direct phase

information. Mass-balance calculations may give

sufficient phase information in some cases, but

can also lead to meaningless results e.g. in the

presence of polymorphs.

It is the complimentary nature of the XRD and

XRFmethods which makes them a valuable

tool for quantitative phase analysis in numerous

applications ranging from scientific research

to industrial high-throughput quality control.

Particularily in mineralogical and geological

application areas, the combined use of XRD and

XRF is booming, offering completely new insights

into materials and processes. Typical examples

are the cement, minerals & mining, and industrial

minerals industries, where the quality of products

and / or efficiency of processes is governed by

both phase and elemental composition. The

combined use of XRD and XRF methods allows

the reliable analysis of materials, for which the

individual methods fail to deliver accurate and

reliable results.

Page 2

Quantitative phase and element analysis of

host/waste rocks and tailings is an important

application in the minerals and mining industry

with respect to both process optimization (e.g.

acid leaching) and environmental protection:

Mining and milling operations are responsible

for the production of billions of tonnes of waste

rock and finely crushed tailings worldwide. An

important application is the knowledge of the

relative amounts of the minerals with acid-

producing or neutralization potential for successful

acid-base accounting with respect to both the

leaching process as well as acid mine drainage,

with its detrimental effects on environment.

As an example, we report combined XRD-XRF

analysis of an intrusive rock with unknown

composition. Of particular interest was its

classification by mineral content as well as

the detection and accurate quantification of

potentially present minerals with significant acid-

producing or neutralization potential.

Powder diffraction data were recorded using a

D4 ENDEAVOR powder diffractometer equipped

with a LynxEye

TM

detector (Fig. 1); the total

measurement time required was about 5 minutes.

For phase identification and quantification,

the DIFFRAC

plus

software packages EVA,

SEARCH and TOPAS were used. Standardless

XRFmeasurements on the same sample were

performed with the S4 PIONEER and the

SPECTRA

plus

software (Fig. 1).

Fig. 1: D4 ENDEAVOR diffractometer (right)

and S4 PIONEER spectrometer (left) connected

with conveyer belt. The D4 is equipped with

Super Speed LynxEye

TM

detector.

Fig. 2: EVA phase identification results.

1) Phase identification

Fig. 2 and Tab. 1 show the XRD powder data and

the phase identification results. The major rock

forming minerals plagioclase, quartz, diopside

and muscovite are easily and correctly identified

in a single default run. Note, that the highly

sensitive SEARCH algorithm clearly prefers albite

(Na-plagioclase) versus anorthite (Ca-plagioclase)

as a result of the slightly different lattice

parameters of both plagioclase solid solution

end members. Best SEARCH figure-of-merits

obtained for the individual phases were 0.65 and

1.48, respectively. Neither ore minerals nor any

K-feldspars or feldspathoids could be detected.

Tab. 1: EVA phase identification results.

SS-VVV-PPPP

Compound Name

00-009-0466 (*)

Albite

00-041-1480 (I)

Albite, calcian

03-065-0466 (C)

Quartz low, syn

01-087-0700 (C)

Diopside, syn

01-089-5402 (C)

Muscovite 2M1

Page 3

Fig. 3: EVA combined XRD-XRF results -

comparison of calculated (column "SQD") versus

observed (column "XRF") element concentrations.

The difference is given in column "Delta".

2) Combined XRD-XRF analysis

To confirm the phase identification results,

and to obtain semi-quantitative phase amount

estimates consistent with the actual elemental

composition of the sample, combined XRD-XRF

analysis has been performed with EVA. EVA

enables semi-quantitative analysis based on the

reference-intensity-ratio (RIR) method using both

XRD as well as XRFdata simultaneously: On

scaling the maximum intensities of the ICDD PDF

patterns to the observed peaks in the powder

pattern, EVA calculates both phase and element

concentrations, and compares the latter with the

actually measured element concentrations.

Element concentrations as obtained by XRF and

used by EVA are provided in Tab. 2. Already at

first glance, the XRF data fully confirm the absence

of any significant acid-producing ore minerals

due to the minor concentrations found for heavy

elements and the absence of sulphur.

Tab. 2: Element concentrations [%] as obtained by XRF.

Oxygen

47.7

Silicon

30.0

Aluminum 9.75

Sodium

6.1

Calcium

3.66

Magnesium 0.456

Iron

1.35

Potassium

0.271

Phosphorus 0.114

Chlorine

0.0445

Titanium

0.252

Manganese 0.0173

Cobalt

0.0182

Nickel

0.0142

Strontium

0.0595

Zirconium

0.0143

Barium

0.0258

Wolfram

0.101

The results for combined XRD-XRF analysis with

EVA are shown in Fig. 3 and Tab. 3. The high Na

vs. Ca concentrations confirm the presence of Na-

plagioclase as found by XRD (diopside accounts

for about 60% of the total Ca, as calculated

by EVA). The present Na-plagioclase is most

successfully modelled using two albite phases

with different Ca amounts. Note the excellent

agreement found between the calculated and

observed element concentrations, which is better

than 1% for all elements, and therefore confirms

the correctness of the XRD phase identification

results for all phases.

The accuracy of the RIR method is limited by

several factors such as preferred orientation

effects and the quality of the ICDD PDF data used

(e.g. quality of relative intensities, I/Icor values,

idealized chemical formula).

Tab. 3: EVA semi-quantitative phase analysis

results based on combined XRD-XRF using

reference intensities as given in the ICDD PDF

patterns.

SS-VVV-PPPP

Compound Name

Phase

amounts

00-009-0466 (*)

Albite

58.2%

00-041-1480 (I)

Albite, calcian

15.4%

03-065-0466 (C) Quartz low, syn

14.0%

01-087-0700 (C) Diopside, syn

9.9%

01-089-5402 (C) Muscovite 2M1

2.6%

The most accurate quantitative results will be

obtained from a TOPAS Rietveld refinement. The

combined XRD-XRF results obtained are of high

value for defining the refinement model.

Page 4

BRUKER AXS, INC.

5465 EAST ChERYL pARKwAY

MADISON, wI 53711-5373

USA

TEL. (+1) (800) 234-XRAY

TEL. (+1) (608) 276-3000

FAX (+1) (608) 276-3006

EMAIL info@bruker-axs.com

www.bruker-axs.com

All configurations and specifications are subject to change without notice. Order No. L88-E00058. © 2006 BRUKER AXS GmbH. Printed in Germany.

BRUKER AXS GMBh

OESTLIChE RhEINBRUECKENSTR. 49

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3) Quantitative TOPAS refinement

Quantitative Rietveld analysis has been

performed using TOPAS, the results are shown

in Fig. 4 and Tab. 4. For the final refinement

two Na-plagioclases with different compositions

have been used to model the data to take the

elemental analysis results into account: Albite (0%

Ca) and Oligoclase (25% Ca).

From the results in Tab. 4 the following

conclusions can be drawn:

1. The sample can be unambiguously classified as

a quartzdiorite according to Streckeisen, see Fig. 5.

2. Combined XRD-XRF analysis and TOPAS

Rietveld refinement can allow a distinction of even

neighboring plagioclase solid solution members

(here albite and oligoclase) if present in sufficient

amounts.

The present sample can be characterised as

a rock with insignificant acid producing or

neutralisation potential. Remarkable is the easy

and reliable determination of the plagioclase type

for estimation of the neutralisation potential. This

ability is of particular interest, as anorthite has

an about 14x higher neutralisation potential than

albite (e.g. Jambor et al., 2002).

Fig. 4: Quantitative TOPAS refinement results.

Tab. 4: Quantitative TOPAS refinement results.

Compound Name

Phase amounts

Albite

49.6%

Oligoclase

30.5%

Quartz

9.9%

Diopside

8.8%

Muscovite

1.2%

Fig. 5: Streckeisen diagram for intrusive rocks.

Q: quartz, A: alkali-feldspar, P: plagioclase.

Reference

J.L. Jambor, J.E. Dutrizac, L.A. Groat, M. Raudsepp.

Environmental Geology (2002) 43, 1-17.

Q

A

P

granite

grano-

diorite

quartz-rich

granodiorite

quartz-

syenite

quartz-

monzonite

quartz-

monzo-

diorite

quartz-

diorite

tonalite

XRD- provides most direct analytical methol for determining presence and absolute amounts of minerals species in sample. XRD can also identify phases

XRF- provides direct information about chemical composition but cannot deliver direct phase information. Mass-balance calculations can be deducted but may lead to useless results in the presence of a polymorph.

The type of crystal structure doesn't affect the transparency. For example a body centered cubic structure is no more and no less transparent than a hexagonal close packed structure. However if the block of substance is a mess of many crystal structures stuck together in no coherent order then yes it does affect the transparency.

Transparency is more dependent on the chemical bonds and the particular light that they absorb. These bond energies are unaffected (ok maybe slightly affected) by the particular crystal structure they find themselves in.

Crystal structure however does have a big influence on the index of refraction of light. You can have left refraction, right refration or even both at the same time depending on the crystal structure.