NIOSH Manual of Analytical Methods (NMAM), Fifth Edition

SYNONYMS: free crystalline silica; silicon dioxide

 QUARTZ in Respirable Coal Mine Dust, by IR (Redeposition) 7603

SiO2 MW: 60.08 CAS: 14808-60-7 RTECS: VV7330000 (quartz) 

METHOD: 7603, Issue 4 EVALUATION: FULL Issue 1: 15 May 1989

Issue 4: 25 July 2017

OSHA: 0.05 mg/m3

NIOSH: 0.05 mg/m3; suspect carcinogen

OTHER OELS: [1,2]

PROPERTIES: solid; d 2.65 g/cm3; crystalline transformation: 

α-quartz to β-quartz @ 573 °C; quartz to tridymite @ 867 °C

SAMPLING

SAMPLER: CYCLONE + PREWEIGHED FILTER (PVC), 

with conductive filter holder

FLOW RATE: ~2 to ~4 L/min, specific for the cyclone 

used

VOL-MIN: 300 L @ 0.1 mg/m3

 -MAX: 1000 L (total dust < 4 mg)

SHIPMENT: Routine

SAMPLE

STABILITY: Stable

BLANKS: 3 field blanks minimum per sample set

ACCURACY

RANGE 

STUDIED: <10 to ~500 μg per sample [3-6]

BIAS: Negligible when matrix effects are 

accounted for

OVERALL

PRECISION (SS�rrrr): 0.07 to 0.10 [3-7]

ACCURACY: ±17% to ±33% [5-7] 

MEASUREMENT

TECHNIQUE: INFRARED SPECTROMETRY

ANALYTE: Quartz

ASHING: Muffle furnace or RF plasma asher

REDEPOSIT: Polypropylene filter (47 mm, 0.45 μm pore 

size) [3]

IR DETECTION: Scan absorbance between 450 cm-1 and 

1000 cm -1

CALIBRATION: Primary certified reference material quartz, 

e.g., NIST SRM 1878b, suspended in 2-

propanol; or NIST SRM 2950a (quartz on

filter)

RANGE: 10 to 500 μg quartz per sample [3-5,7]

ESTIMATED LOD: 1 μg [3,4] 

PRECISION (SS�rr): 0.004 to 0.10 @ 50 to 250 μg per sample [3-

6]

APPLICABILITY: The working range is 0.01 to 0.50 mg/m3 for a 1000-L air sample [3,5-7]. The method was originally developed 

specifically for respirable coal mine dust samples [6,8-10]. IR is useful for a matrix such as coal mine dust, where the interferences 

can be predictably removed and minimized.

INTERFERENCES: Amorphous silica, kaolinite, muscovite, talc, albite, vermiculite and other minerals that absorb IR radiation in 

the 800 cm-1 region are potential interferences to RCS measurement [11,12] [Table 1]. Potentially interfering silicates can be 

removed using a phosphoric acid cleanup procedure [13]. Calcite at >20% dust loading can negatively interfere by reacting with 

quartz during muffle ashing [10,14]. The sample preparation procedures described in this method enable minimization of

potential interferences.

OTHER METHODS: NIOSH Method 7602 describes sample preparation and IR measurement of respirable crystalline silica (RCS) by 

means of a KBr pellet [15]. X-ray diffraction (e.g., NIOSH Method 7500 [15]) is a complementary method for quartz measurement by 

IR. MSHA Method P-7 [6] is an equivalent IR method for respirable quartz. An international voluntary consensus standard 

describing the measurement of RCS by IR spectrometry, ASTM D7439, has been promulgated [16].
QUARTZ IN RESPIRABLE COAL DUST BY IR (Redeposition): METHOD 7603, Issue 4, dated 25 July 2017 - Page 2 of 8 

NIOSH Manual of Analytical Methods (NMAM), Fifth Edition

REAGENTS:

1. Quartz primary certified reference material 

(CRM); e.g., NIST SRM 1878b or SRM 2950a 

[17]. 

2. Kaolinite CRM; e.g., material meeting 

requirements from USP#

3. Deionized water, ≥18 MΩ-cm resistivity. 

4. 2-Propanol, reagent grade.

5. Ethanol, 95%, for cleaning of sampling 

equipment.*

6. Hydrochloric acid* (HCl) solution, 25% v/v: 

Add 25 mL conc. HCl (37% w/w) to 50 mL 

with deionized water, cool, and bring to 100 

mL with deionized water.

NOTE: Required if calcite is present and 

samples are prepared using a muffle 

furnace.

7. Calibration stock solution (quartz 

suspension in 2-propanol), 15 mg/L: 

Accurately weigh 7.5 mg of quartz and add 

to about 400 mL of 2-propanol in a 500-mL 

volumetric flask. Bring the suspension to the 

mark with 2-propanol. 

8. Kaolinite suspension, 100 mg/mL: 

Accurately weigh 50 mg of dried kaolinite

and add to about 400 mL of 2-propanol in a 

500-mL volumetric flask. Bring the 

suspension to the mark with 2-propanol.

NOTE: Not required if muffle furnace used 

for sample ashing.

9. Desiccant.

10. Oxygen, purified.

#

United States Pharmacopeia Convention

*See SPECIAL PRECAUTIONS.

EQUIPMENT:

1. Sampler:

a. Filters, 37-mm dia., 5-μm pore size, 

polyvinyl chloride (PVC), supported with 

backup pad or screen in 2-piece, 

conductive / static-dissipative filter holder.

b. Cyclone, respirable, designed to operate at

a flow rate of ≈2 or ≈4 L/min, specific for 

each sampling device. 

c. Sampling head holder, for keeping the 

cassette, cyclone and coupler tightly 

together so that air enters only through

cyclone inlet.

2. Personal sampling pumps, for sample 

collection at ≈2 or ≈4 L/min.

3. Infrared spectrometer, double-beam 

dispersive or Fourier transform device, with 4 

cm-1 resolution or better.

4. Filtration apparatus (for redepositing sample 

after ashing), consisting of fritted support, 

side-arm vacuum flask and glass filtration 

funnel with bakelite base, 1.0 cm internal 

diameter. The base should seal tightly to the 

fritted support to prevent leakage.

5. Filters for standards and redeposition, 47-

mm, 0.45-μm pore size, polypropylene (PP).

6. Glass fiber filters, 25-mm dia., for backup 

during filtration. 

7. Filtration funnel for treating filters (required 

only if using a muffle furnace): same as in 6. 

above except with funnel i.d. about 1.6 cm 

and with 0.5-μm pore size 37-mm dia. PVC 

filters to recollect residue.

8. Low-temperature (RF plasma) asher and 

aluminum weighing pan, or muffle furnace 

and 10-mL porcelain crucibles (with covers). 

9. Analytical balance, capable of weighing to 

the nearest 0.001 mg.

10. Ultrasonic bath. 

11. Desiccator. 

12. Beakers, 50-mL. 

13. Magnetic stirrer with insulated top. 

14. Volumetric flasks with stoppers, 500-mL.

15. Tweezers and metal spatulas.

16. Petri dishes, for 47-mm dia. filters.

17. Wash bottles.

18. Pipets, various sizes as required.
QUARTZ IN RESPIRABLE COAL DUST BY IR (Redeposition): METHOD 7603, Issue 4, dated 25 July 2017 - Page 3 of 8 

NIOSH Manual of Analytical Methods (NMAM), Fifth Edition

SPECIAL PRECAUTIONS: Wear appropriate personal protection during sampling activities, sample 

preparation and analysis. It is essential that suitable gloves, eye protection, laboratory coat, etc., be used, 

especially when working with concentrated acids. Ethanol and 2-propanol are flammable. Avoid exposure

by inhalation of silica dust or acid fumes. Perform sample preparation and analysis in a clean, wellventilated area that is well removed from any possible contamination. Any skin affected by exposure to 

acids must be immediately washed with plenty of water. 

SAMPLING:

1. Calibrate each personal sampling pump with a representative sampler in line. Use conductive filter 

holders.

2. Pre-weigh each filter to the nearest 0.01 mg.

3. Sample at ≈2 L/min [18] or ≈4 L/min [5] using a pump set at a specific flow rate for a selected cyclone,

designed to collect the respirable aerosol fraction (in accordance with ISO 7708[19]), for a total sample 

size of 400 to 1000 L. Take care not to overload the filter.

NOTE 1: Do not allow the sampler assembly to be inverted at any time when using a cyclone. Turning 

the cyclone to anything more than a horizontal orientation may deposit oversized material 

from the cyclone body onto the filter.

NOTE 2: Higher sampling flow rates may be suitable for certain sampler designs [20].

4. After collection of samples, remove the filter holders from the cyclones. Seal the filter holders 

(cassettes) and transport them to the laboratory in a container designed to prevent damage in transit.

SAMPLE PREPARATION:

5. Remove the filters from filter holders and, after preconditioning to ambient conditions, re-weigh the 

filters to the nearest 0.01 mg; the difference is the sample weight, Ws (μg).

6. Use one of the following methods to prepare samples and blanks:

a. Low-temperature (RF plasma) asher: Transfer the weighed filters to clean 50-mL beakers. Place the 

beakers in the low-temperature asher so that sample exposure to the plasma is optimized. Ash the 

samples for 2 h at 300 W RF power and oxygen flow rate of 75 mL/min, according to manufacturer’s 

instructions. Carefully bring the asher to atmospheric pressure, remove the beakers, and add 15 mL 

2-propanol to each beaker. 

b. Muffle furnace: For samples expected to contain a significant amount of calcite (>20% of the total 

dust loading), wash filters with 25% v/v HCl using the filtration apparatus with the 1.6-cm i.d. glass 

funnel. For other samples, proceed to step 6.b.ii. 

i. Place a 25-mm glass fiber filter over the frit area of the filtration funnel, then place a 0.45-μm 

pore size, 37-mm dia. PP filter atop the glass fiber filter. Clamp the funnel over the frit and 

ensure that there is no leakage. Using tweezers and gloved hands, take the weighed sample 

filter and fold it in half with the collection surface inside, then fold again into quarters, and place 

the folded filter into the funnel. Add 10 mL of 25% HCl (v/v), then 5 mL of 2-propanol; allow to 

stand for 5 min. Apply vacuum and slowly aspirate the acid and alcohol in the funnel. Press the 

folded sample filter onto the surface of the collection filter if necessary to remove all liquid. 

Release vacuum, remove both filters and place in a porcelain crucible. Allow to air-dry.

ii. Place filter samples and blanks in porcelain crucibles, loosely cover, and ash in muffle furnace for 

2 h at 600  ̊C (800  ̊C if graphite present). Allow to cool to room temperature.

iii. Add ~3 mL 2-propanol to the ash within each crucible, scrape the crucible to loosen all particles, 

and quantitatively transfer to contents to a 50-mL beaker. Wash the crucible several times with 

2-propanol and add the wash to the beaker. Add 2-propanol to the beaker to bring the volume 

to ~15 mL.

7. Redeposit the sample residue as follows, using the filtration apparatus with the 1.0 cm dia. funnel. 

With a slight vacuum applied, place a 25-mm glass fiber filter on the fritted base. Cut a 47-mm 

0.45-μm PP filter in half. Superimpose one half over the other, glossy sides down, and place on the 
QUARTZ IN RESPIRABLE COAL DUST BY IR (Redeposition): METHOD 7603, Issue 4, dated 25 July 2017 - Page 4 of 8 

NIOSH Manual of Analytical Methods (NMAM), Fifth Edition

glass fiber filter. (The lower half of the PP filter serves as a blank for use in the reference beam of the IR 

spectrometer.) Position the filter funnel, apply clamp, turn off vacuum and ensure that there is no

leakage. Place sample beakers from step 6.b.iii into ultrasonic bath for at least 30 sec to ensure 

homogeneous dispersion. Remove each beaker, wipe off excess water from the outside of the beaker, 

and transfer the slurry to the filtration funnel. Reapply vacuum and, during filtration, rinse the beaker 

twice with 2-propanol to ensure quantitative transfer of entire contents to the funnel. Control the 

filtration rate to keep the liquid near the top of the funnel during rinsing to avoid disturbing the 

deposit. When the depth of liquid in the funnel reaches about 4 cm above the filter, gently rinse the 

inside of the funnel with 2-propanol and complete filtration. Remove clamp and funnel, taking care 

not to disturb the deposit. Release the vacuum. Define the deposit area by marking around the 

circumference using a pencil or scriber. (This is especially important for standards or light-colored 

samples.) Place the PP filter halves in Petri dishes and allow to air dry.

CALIBRATION AND QUALITY CONTROL:

8. Prepare at least 5 working standard quartz filters. Calibration standards shall be prepared from 

primary CRMs of known purity, particle size range and homogeneity. 

NOTE: Suitable quartz standards include primary reference materials such as NIST SRM 1878b or 2950; 

the use of secondary reference materials as calibration standards is not appropriate for IR 

measurement [14]. 

a. Place the flask containing the calibration stock solution in an ultrasonic bath for 30-45 min. 

b. Move the flask to a magnetic stirrer and stir slowly while the flask cools to room temperature. 

Continue slow stirring while preparing calibration standards.

c. Mount a PP filter in the filtration apparatus in the same manner used to redeposit the samples. Add 

5 mL of 2-propanol to the funnel. Withdraw an aliquot of the quartz suspension from the center of 

the flask. Draw liquid to the mark but do not attempt to adjust volume by draining pipet. Carefully 

wipe the outside of the pipet, then drain the suspension into the filter funnel. Rinse down the 

inside wall of the pipet with a few mL of 2-propanol, draining the washings into the funnel. Apply 

vacuum to complete the filtration. Prepare quartz standards in this manner to cover the range 10 

to 250 μg per filter.

d. Carry an additional set of these calibration standards and media blanks through steps 6 and 7 to 

monitor for contamination and losses.

NOTE: Accuracy depends on obtaining uniform deposition of samples and calibration standards 

across the filter surface and obtaining reproducible aliquots from the quartz suspension. 

This requires skill and practice. The quartz calibration curve should be prepared before 

analyzing samples as a check on the analyst’s ability to prepare uniform deposits. 

Repeatability should be <10% on replicate calibration standards with >40 μg of quartz.

9. Perform IR scans for each standard filter using the other half of the filter in the reference beam (see 

Measurement section). Construct a calibration graph of absorbance at 800 cm-1 vs. μg of quartz per 

filter. The plot should be linear and pass through the origin.

10. If samples were low-temperature ashed and kaolinite is known to be present in the matrix of the 

collected samples, prepare at least five different loadings of PP filters containing 100 to 600 μg of 

kaolinite. Measure the IR absorbance of kaolinite standards from 1000 cm-1 to 650 cm-1. Prepare a 

graph with absorbance at 915 cm-1 as ordinate vs. absorbance at 800 cm-1 as abscissa. Use the 

relationship between the quartz and kaolinite peak to correct the absorbance value at 800 cm-1

samples containing kaolinite [20]. 

11. Carry media blanks and filters spiked with known amounts of quartz through the sample preparation 

procedures to monitor for contamination and losses. 

NOTE: Knowledge of and training in geochemistry and mineralogy is strongly recommended for users 

of this method. Although many analytical chemists are familiar with IR spectroscopy (e.g., as 

applied to organic analysis), mineralogical samples such as those containing RCS require 
QUARTZ IN RESPIRABLE COAL DUST BY IR (Redeposition): METHOD 7603, Issue 4, dated 25 July 2017 - Page 5 of 8 

NIOSH Manual of Analytical Methods (NMAM), Fifth Edition

additional knowledge of geochemistry and mineralogy to correctly interpret IR spectra and 

account for matrix interferences and mineral transformations.

MEASUREMENT:

12. Set the infrared spectrometer to double-beam absorbance mode and to the appropriate settings for 

quantitative analysis. For each IR scan, place a PP sample filter half in the sample beam and a PP blank 

filter half in the reference beam, and obtain a spectrum at 4 cm-1 resolution or better from 450 cm-1 to 

1000 cm-1. For each PP filter sample, center the IR beam on filter deposit.

13. Draw an appropriate baseline under the absorbance band at 800 cm-1 from approximately 820 to 670 

cm-1. Measure the absorbance from the 800 cm-1 peak maximum to baseline in absorbance units. 

NOTE: If the peak at 800 cm-1 is small, expand the ordinate to enhance the peak height. 

14. If the sample was ashed at low temperature, the presence of kaolinite will be indicated by an 

absorption band with maximum at 915 cm-1. Draw an appropriate baseline under the absorbance 

band at 915 cm-1 from approximately 960 to 860 cm-1. Measure the absorbance from the 915 cm-1 peak 

maximum to baseline.

15. Analyze blanks and, if necessary, correct baseline.

CALCULATIONS:

16. To correct for the presence of kaolinite (if necessary), use the measured absorbance at 915 cm-1 and 

refer to the kaolinite curve to establish the corrected absorbance for quartz at 800 cm-1 [21]. Use this 

corrected absorbance value at 800 cm-1 in calculating the airborne quartz concentration. 

17. If correction for kaolinite is not required, use the measured (uncorrected) absorbance at 800 cm-1 to 

determine the weight (Ws, μg) quartz from the calibration graph. 

18. From the weight of quartz (Ws, μg), calculate its concentration, C (mg/m3

), in the volume of air 

sampled, V (L):

C = [Ws / V], mg/m3

19. If percent quartz (%Q) is of interest, divide the weight of quartz, Ws (μg), by the total sample weight, Wt

(μg): 

%Q = [Ws / Wt] × 100

EVALUATION OF METHOD:

The method is based on MSHA method P-7, which was collaboratively tested [4] and optimized [6]. 

Interlaboratory evaluation included a ruggedization step to test the effects of the use of muffle furnace or 

plasma asher, amount of calcite or kaolinite in the sample, ashing time, pH of solvent used to remove 

calcite, shipment of samples, and other factors. None of these contributions was found to have a 

statistically significant effect. Filter collection has been carried out using respirable cyclone samplers with 

flow rate ≈2 L/min [4] and ≈4 L/min [5], with sampling volumes ranging from 300 to 1000 L; analysis was 

subsequently carried out using the redeposition method. Applicable analytical ranges were from 3 μg [5] 

to 500 μg quartz [4,6] per sample, with estimated method detection limits (MDLs) of 1-5 μg or even less [3]. 

Reported precision estimates, in terms of relative standard deviation, were 0.10 or below at quartz mass 

per sample of 20-400 μg [3-6]. The IR redeposition method has been used extensively to measure the 

quartz content of respirable dusts collected in coal mines [3,8-10,21,22]. Laboratories using the IR 

redeposition method have performed successfully in interlaboratory proficiency analytical testing 

programs [7, 23, 24].
QUARTZ IN RESPIRABLE COAL DUST BY IR (Redeposition): METHOD 7603, Issue 4, dated 25 July 2017 - Page 6 of 8 

NIOSH Manual of Analytical Methods (NMAM), Fifth Edition

REFERENCES:

[1] ACGIH [2017] TLVs and BEIs based on the documentation of the Threshold Limit Values for chemical 

substances and physical agents and Biological Exposure Indices. Cincinnati, OH: American 

Conference of Governmental Industrial Hygienists.

[2] Institute for Occupational Safety and Health of the German Social Accident Insurance (IFA) [2017]. 

GESTIS international limit values, http://limitvalue.ifa.dguv.de/. 

[3] Farcas D, Lee T, Chisholm WP, Soo J-C, Harper M [2016]. Replacement of filters for respirable quartz 

measurement in coal mine dust by infrared spectroscopy. J Occup Environ Hyg 13:D17-D22. 

[4] Anderson CC [1983]. Collaborative test of two methods for determining free silica in airborne dust. 

Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control, National 

Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 83-124. 

[5] Lee T, Lee EG, Kim SW, Chisholm WP, Kashon M, Harper M [2012]. Quartz measurement in coal dust 

with high flow rate samplers – Laboratory study. Ann Occup Hyg 56:413-425. 

[6] Mine Safety and Health Administration (MSHA) [2013]. Infrared determination of quartz in respirable 

coal mine dust; Method No. P-7. Pittsburgh, PA: MSHA. 

[7] Harper M, Sarkisian K, Andrew M [2014]. Assessment of respirable crystalline silica using Proficiency 

Analytical Testing results from 2003-2013. J Occup Environ Hyg 11:D157-D163. 

[8] Larsen DJ, von Loenhoff LJ, Crable JV [1972]. The quantitative determination of quartz in coal dust 

by infrared spectroscopy. Am Ind Hyg Assoc J 33:367-372. 

[9] Freedman RW, Toma SZ, Lang HW [1974]. On-filter analysis of quartz in respiratory coal dust by 

infrared absorption and x-ray diffraction. Am Ind Hyg Assoc J 35:411-418. 

[10] NIOSH [1977]. Method P&CAM 100 - Quartz in coal dust by infrared spectroscopy. In: Taylor DG, ed. 

NIOSH manual of analytical methods, 2nd ed. Cincinnati, OH: U.S. Department of Health, Education 

and Welfare, Center for Disease Control, National Institute for Occupational Safety and Health, 

DHEW (NIOSH) Publication No. 77-157. 

[11] Taylor DG, Nenadic CM, Crable JV [1970]. Infrared spectra for mineral identification. Am Ind Hyg 

Assoc J 31:100-108. 

[12] Ojima J [2003]. Determining crystalline silica in respirable samples by infrared spectrophotometry in 

the presence of interferences. J Occup Health 45:94-103. 

[13] Talvitie NA [1951]. Determination of quartz in the presence of silicates using phosphoric acid. Anal 

Chem 23:623-626. 

[14] NIOSH [2003]. Determination of airborne respirable silica (Chapter R). By Key-Schwartz RJ, Baron PA, 

Bartley DL, Rice FL, Schlecht PC. In: NIOSH manual of analytical methods, 4th ed.; Schlecht PC, 

O’Connor PF, eds. Cincinnati, OH: U.S. Department of Health and Human Services, Centers for 

Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication 

No. 94-113. 

[15] NIOSH [2003]. Methods 7603 and 7500. In: NIOSH manual of analytical methods, 4th ed.; Schlecht PC, 

O’Connor PF, eds. Cincinnati, OH: U.S. Department of Health and Human Services, Centers for 

Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication 

No. 94-113. 
QUARTZ IN RESPIRABLE COAL DUST BY IR (Redeposition): METHOD 7603, Issue 4, dated 25 July 2017 - Page 7 of 8 

NIOSH Manual of Analytical Methods (NMAM), Fifth Edition

[16] ASTM International [2014]. ASTM D7948, Standard test method for measurement of respirable

crystalline silica in workplace air by infrared spectrometry. West Conshohocken, PA: ASTM

International.

[17] NIST [no date]. Standard reference materials (SRMs). Gaithersburg, MD: U.S. Department of

Commerce, National Institute of Standards and Technology, https://www.nist.gov. Date accessed:

July 25, 2017.

[18] Stacey P, Mecchia M, Verpaele S, Pretorius C, Key-Schwartz R, Mattenklott M [2014]. Differences

between samplers for respirable dust and the analysis of quartz – An international study. In: Silica

and associated respirable mineral particles (ASTM STP 1565); Harper M, Lee T, eds. W.

Conshohocken, PA: ASTM International; pp. 73-102.

[19] ISO [1995]. Air quality – Particle size fraction definitions for health-related sampling. Geneva,

Switzerland: International Organization for Standardization.

[20] Verpaele S, Jouret J [2013]. A comparison of the performance of samplers for respirable dust in

workplaces and laboratory analysis for respirable quartz. Ann Occup Hyg 57:54–62.

[21] Lee T, Chisholm WP, Kashon M, Key-Schwartz RJ, Harper M [2013]. Consideration of kaolinite

interference correction for quartz measurements in coal mine dust. J Occup Environ Hyg 10:425-434.

[22] Ainsworth, SM [2005]. Infrared analysis of respirable coal mine dust for quartz: Thirty five years. J

ASTM Int 2(4):1-13, DOI: 10.1520/JAI12231.

[23] Shulman SA, Groff JH, Abell MT [1992]. Performance of laboratories measuring silica in the

Proficiency Analytical Testing program. Am Ind Hyg Assoc J 53:49-56.

[24] Stacey P, Tylee B, Bard D, Atkinson R [2003]. The performance of laboratories analyzing α-quartz in

the Workplace Analysis Scheme for Proficiency. Ann Occup Hyg 47:269-277. 

METHOD REVISED BY:

Kevin Ashley, Ph.D., Rosa J. Key-Schwartz, Ph.D., and Martin Harper, Ph.D., CIH, CDC/NIOSH. 

Disclaimer: Mention of any company or product does not constitute endorsement by NIOSH. In addition, 

citations to websites external to NIOSH do not constitute NIOSH endorsement of the sponsoring 

organizations or their programs or products. Furthermore, NIOSH is not responsible for the content of 

these websites. All web addresses referenced in this document were accessible as of the publication date.
QUARTZ IN RESPIRABLE COAL DUST BY IR (Redeposition): METHOD 7603, Issue 4, dated 25 July 2017 - Page 8 of 8 

NIOSH Manual of Analytical Methods (NMAM), Fifth Edition

Table 1. Minerals potentially encountered and their characteristic IR bands (450-1000 cm-1) 

Mineral Major/Interfering Peaks, cm-1 Identifying Peaks, cm-1

Quartz 800, 780 694, 512, 467

Cristobalite 798 623, 490

Tridymite 789 617, 476

Amorphous silica 800 464

Kaolinite 795, 754 915, 547, 474

Muscovite 800, 750 535, 481

Mullite 837, 748 556, 468

Pyrophyllite 830, 814 948, 477, 457

Albite 788, 746 726, 652, 598, 470

Montmorillonite 797 918, 668, 526, 470

Daphnite 798, 771 667, 610, 539, 467

Anorthite 760, 730 577, 538, 481

Orthoclase 765, 745, 730 645, 593, 540

Talc 797, 778 668, 641, 620

Vermiculite 810, 755 685, 510