F-19 Freeway Cutting, Abbotsford, City of Yarra, Victoria, Australiai

Regional Level Types
F-19 Freeway Cutting	- not defined -
Abbotsford	- not defined -
City of Yarra	Municipality
Victoria	State
Australia	Country

Description: "Aragonite has been found generally in vesicular basalt above the zeolite zones. Mamillary calcite is a common associated carbonate. Spectacular aragonite sprays, white or yellow and measuring up to 60 mm across, have been collected."

Description: Ferroan calcite is by far the most common type of calcite at the F19 cuttings. Normal calcite occurs as white to cream mammillary coatings lining cavities along with aragonite crystal sprays.

Description: "Ferroan calcite is abundant and is intimately associated with the zeolites. The calcites are various shades of yellow, orange and brown, are translucent to opaque, and occur in a number of spectacular forms such as clubs which sometimes taper to fragile stems providing the point of attachment to the matrix; 'bow-ties'; hemispheres and nodules. The various structures are usually made up of tightly packed fibres which give a silky appearance to the specimen when held in a certain direction. Calcite also occurs as yellowish brown glassy prisms. Simple calcite rhombs are rare, although 'dog-tooth spar' is not uncommon."

Description: "Chabazite occurs as colourless, water-clear sparkling crystals, which usually rapidly dehydrate and become opaque and crazed upon exposure. Micro crystals are very much less affected. The crystals are always twinned, and simple chabazite rhombs, or forms dominated by the rhomb, have never been observed in Melbourne Basalt. The 'phacolite' form and complex clusters based on this unit, are exceedingly common and alternative forms are rare. The terminal plane is always domed and has a frosted or etched appearance." Single phacolite type crystals occur up to 12 mm across and complex twin/clusters occur up to 20 mm across.

Description: "The gonnardite/natrolite intergrowth, considered mesolite prior to 1988, has been verified from all Melbourne localities, and occurs as small, opaque white hemispheres and tufts composed of radiating fibres and prismatic needles. The individual groups have diameters up to 6 mm, though typically are 1 to 3 mm. The groups show a variety of lustre-chalky, sub-vitreous or silky- and the prismatic needles appear quite glassy when viewed through the microscope. The clusters that have been studied are radially zoned, presenting a compact gonnargite-rich core and a soft fibrous natrolite-rich outer zone."

Description: Mesolite recorded from this locality has proven to be a intergrowth of natrolite and gonnardite.

Description: "The gonnardite/natrolite intergrowth, considered mesolite prior to 1988, has been verified from all Melbourne localities, and occurs as small, opaque white hemispheres and tufts composed of radiating fibres and prismatic needles. The individual groups have diameters up to 6 mm, though typically are 1 to 3 mm. The groups show a variety of lustre-chalky, sub-vitreous or silky- and the prismatic needles appear quite glassy when viewed through the microscope. The clusters that have been studied are radially zoned, presenting a compact gonnargite-rich core and a soft fibrous natrolite-rich outer zone."

Description: "In common with chabazite, phillipsite is always found in complex twinned crystals, with smaller crystals generally showing the simple forms such as the fourling, the prismatic and cruciform eightling and clusters based on these. Varieties of the larger crystals include the 'double cross', clusters based on this twinned form, and exceedingly complex rosettes and hemispheres and blocky aggregates. In freshly opened cavities, crystals of phillipsite are colourless to water-clear, but the larger crystals, like those of chabazite, soon become translucent to opaque-white when allowed to dehydrate upon exposure."