STAINING TECHNIQUES FOR GEOMATERIALS PETROGRAPHY - Geomaterials: Under the Microscope - page 171

Subject Method summary* Observation

Tucker 3 describes a simple technique to visualize the

Clay Clay minerals take up the stain.

minerals distribution of clays in sandstones and argillaceous

limestone: soak grease-free specimen surfaces in
solution of 0.5 g malachite green, congo red, or
methylene blue in 250 ml of water (choose the dye
colour that contrasts most with the rock). Also,
replacing half of the water with ethanol or methanol
works well on limestones, including chalk.

Poole and Thomas 8 method for sulfate minerals :

Sulfate Gypsum, anhydrite, ettringite, and

minerals 2 min immersion in 2:1 mixture of BaCl 2 :KMnO4 6% gypsum plasters stain pink to purple.

solution, wash first with water then saturated oxalic
acid.
Friedman 9 method for sulfate minerals : a few Gypsum stains purple, anhydrite and

minutes' immersion in a cold solution of 0.1-0.2 g calcite remain unstained, while

Alizarin Red S in 25 ml of methanol added to 50 ml dolomite stains very pale purple.

of 5% sodium hydroxide.
Hounslow 10 method for gypsum and anhydrite : a few

Gypsum and anhydrite stain yellow.

seconds' immersion in a 10% solution of mercuric
nitrate acidified by 1% nitric acid.

Natesaiyer and Hover 11,12 method: 15 min immersion

Alkali-silica Ultraviolet light at 240 nm wavelength

gel in 19% uranyl acetate 1.5% acetic acid solution, gives alkali-silica gel a green

wash in water. fluorescence.

Poole, McLachlan, and Ellis 13 method: immerse in 4M

Alkali-silica gel in concrete voids and

cuprammonium sultate for 72 h and then wash in cracks stain blue.

water.
Guthrie and Carey method 14,15 : immerse in saturated Alkali-rich alkali-silica gel stains bright

solution of sodium cobaltnitrate, followed by yellow. Calcium-rich gel stains pink.

immersion in Rhodamine B base solution.

* Full method details and safety requirements contained in the original references (listed below) should be consulted before a method is used

for the first time.

1 Dickson JAD (1965). A modified staining technique for carbonates in thin section. Nature 205 :587.
2 Dickson JAD (1966). Carbonate identification and genesis as reveled by staining. Journal of Sedimentary Petrology
361/2 :491-505.
3 Tucker M (ed) (1988). Techniques in Sedimentology . Blackwell Science Ltd, London.
4 Haines M (1968). Two staining tests for brucite in marble. Mineralogical Magazine 36 :886-888.
5 Fiegl F (1937). Qualitative Analysis by Spot Tests . Nordemann, New York.
6 Houghton HF (1980). Refined techniques for staining plagioclase and alkali feldspars in thin section. Journal of
Sedimentary Petrology 50 :629-631.
7 Shand SJ (1939). On staining of feldspathoids and on zonal structure of nepheline. American Mineralogist 24 :508-513.
8 Poole AB, Thomas A (1975). A staining technique for the identification of sulfates in aggregates and concrete.
Mineralogical Magazine 40 :315-316.
9 Friedman GM (1959). Identification of carbonate minerals by staining methods. Journal of Sedimentary Petrology 29 :87-97.
10 Hounslow AW (1979). Modified gypsum/anhydrite stain. Journal of Sedimentary Petrology 49 :636-637.
11 Natesaiyer KC, Hover KC (1988). In situ identification of ASR products in concrete. Cement and Concrete Research 18 :455-
463.
12 Natesaiyer KC, Hover KC (1989). Further study of in situ identification method for alkali-silica reaction products in
concrete. Cement and Concrete Research 19 :770-778.
13 Poole AB, McLachlan A, Ellis DJ (1988). A simple staining technique for the identification of alkali-silica gel in concrete
and aggregate. Cement and Concrete Research 18 :116-120.
14 Guthrie GD, Carey JW (1997). A simple environmentally friendly and chemically specific method for the identification and
evaluation of alkali-silica gel. Cement and Concrete Research 27/9 :1407-1417.
15 Guthrie GD, Carey JW (1998). A Geochemical Method for the Identification of ASR Gel . TRB Paper No. 991261.
Transportation Research Board, Washington, USA.