The mineral part of analysed samples is composed of clays, feldspars, carbonates, analcime
, natrolite, quartz and bassanite (Table 1).
There are many species of zeolites, such as Analcime
, Chabazite, Clinoptilolite, Faujasite, Ferrierite, Heulandite, Laumontite, Mordenite.
DRX also indicated the minerals biotite, analcime
, aegirine and balliranoite (Figure 1).
His description is easy to follow, and he noted a place of special interest at Wasson Bluff: "Opposite the Two Islands, the fissures of the trap are lined with fine crystals of analcime
and natrolite; and the fissures and vacant spaces of the trap conglomerate in the same neighbourhood contain a reddish variety of chabasie [chabasite] in rhombohedrons, often of large size" (Dawson 1855, p.
The matrix also shows analcime
and calcite, mostly as later filling and cementing material.
Analyzed is constituted by chlorite, muscovite, quartz, calcite and analcime
(Huerta, et al.
Thomsonite varies in habit showing bladed crystals, spherulites, radial crystal groups and rich coatings mainly made up of small crystals, although it sometimes has a fibrous nature Analcime
appears as vitreous and granular well-formed trapezohedral crystals which are often colourless and sometimes white Natrolite is generally beige to white, either massive or forming radiating fibers and shows a more glassy brightness than mesolite, which is generally milky white and fibrous, having larger fibers than those of natrolite Stilbite commonly occurs as vitreous sheaves or plates, ranging from colourless to green to white
Significant mineral occurrences in the country's non-igneous and non-metamorphic rocks are uncommon, although beautiful celestine specimens come from sedimentary rocks (marls) near Majunga, and well-crystallized zeolites such as gmelinite, analcime
and chabazite were found in volcanic rocks at some historical localities (Lacroix, 1922-23; Behier, 1960).
The deep-sea volcanogenic accumulations interlayered with basalt effusives contain the following secondary silicates in semiquantitative relations: saponite > analcime
, wairakite > chlorite, actinolite, tremolite > heulandite, clinoptilolite (?
English PM (2001) Formation of analcime
and moganite at Lake Lewis, central Australia: significance of groundwater evolution in diagenesis.
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 observed trend; unalterred glass [greater than] smectite [greater than] Nachabazite [greater than] analcime
+ phillipsite [greater than] K-feldspar [greater than] illite [greater than] albite + tobermorite, is similar to that formed following the deposition of volcanogenic glass in saline-alkaline lakes.