Caption: Figure 4: X-ray diffraction of coal gangue after [Na.sub.2]C[O.sub.3] activation and [H.sub.2]S[O.sub.4] wash and typical chemical formula of the mineral components: quartz (Si[O.sub.2]), kaolinite ([Al.sub.2][Si.sub.2][O.sub.5][(OH).sub.4]), albite (NaAl[Si.sub.3][O.sub.8]), nepheline (K[Na.sub.3][(AlSi[O.sub.4]).sub.4]), lime (CaO), sodium silicate ([Na.sub.2]O-nSi[O.sub.2]), illite (K[Al.sub.2] [(Al,Si)Si3[O.sub.10]]), ankerite (CaMg[(C[O.sub.3]).sub.2]), siderite (FeC[O.sub.3]), and gismondine
Accordingly, the alkaline hydration reaction of the alternative cementitious material possibly produces sodium and/or calcium alumino silicate based compounds such as sodalite, natrite, gismondine
, calcium silicate hydrate gel, sodium alumino silicate hydrate gel, and calcium sodium alumino silicate hydrate gel [5, 26].
Formation of the aluminosilicate zeolite gismondine
is also observed.
In the spectra of exposed specimens, peaks due to gismondine
be came quite prominent including those of albite and chabazite.
The present study was prompted by a serendipitous discovery of well-formed crystals of gismondine, chabazite-Ca and mesolite in a road cut near Laurel, Quebec, by Canadian Museum of Nature staff in 1983.
Gismondine Ca[[Al.sub.2][Si.sub.2][O.sub.8]] x 4.5[H.sub.2]O
Short mineralogical notes on natrolite, thomsonite, phillipsite, gismondine and analcime assemblages were presented by Muhlstein and Fengl (1977), gmelinite by Barta and Rychly (1979) and Rychly et al.
The zeolites, such as analcime, gismondine, natrolite, thomsonite, and barium-bearing phillipsite-Ca were observed in irregular vugs and larger amyg-daloidal cavities within the zeolitized trachyandesite facies.
However, adding activated silica fume into cement-stabilized soil mixed with seawater promotes the early hydration products at the initial period of cement hydration, resulting in the fact that the content in early hydrated calcium silicate (XRD studies show that calcium silicate hydrate crystals are [Ca.sub.2]Si[O.sub.4] x 0.35[H.sub.2]O with a calcium silicon ratio C/S = 2 > 1.5, which belongs to a high alkaline calcium silicate hydrate) and hydrated calcium aluminosilicate (also known as gismondine
, CaO x [Al.sub.2][O.sub.3] x 2Si[O.sub.2] x 4[H.sub.2]O) is being higher and exhibiting high diffraction peaks.
(= roggianite) (1997), 1571 Gismondite (= gismondine
) Coombs et al.: Can.
The type localities for no less than eight of the approximately 49 known zeolites (barrerite, dachiardite, gismondine
, merlinoite, montesommaite, phillipsite, pollucite, and willhendersonite) are within its borders.