Chalcedony After Calcite Pseudomorph from Lyndhurst NSW

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What we have here is an Australian pseudomorph, of chalcedony replacing calcite. Pretty cool seeing how uncommon it is!

Greg from Blue Gems was able to source and share some great information regarding these specimens. These were found by a farmer by the name of Ron Green on a property in Lyndhurst near Neville. Lyndhurst is a small village in New South Wales, Australia in Blayney Shire. It’s 4km west of Mandurama or about 269km west of Sydney and 63km south-west of Bathurst just off the Mid-Western Highway New South Wales.

Ron was a mineral collector and located a seam of this pseudomorph around 20cm wide and about 3 metres long in the early 1990’s. All of the known specimens of this chalcedony replacing calcite came from Ron who has sadly passed away and his collection was purchased by Tony and Johanna Van De Vorstenbosch. This specimen would have originally came from them.

Greg had it identified by Patrick Murphy in Adelaide who was a pseudomorph collector and by the hardness concluded it was chalcedony after calcite. These are very rare and the deposit would now be inaccessible.

I acquired this specimen from Tony Noel at the National Gem & Mineral Show, Gemboree in Lithgow – April 2017.

Specimen Details

Chemical Formula: SiO2

ID #: JG0138, JG0139, JG0140

Colour: White, beige

Hardness: 3.5 – 4

Acquisition Date: 15/04/2017

Crystal System: Hexagonal

Lustre: Vitreous, waxy, or dull

Dimensions: 66mm x 50mm x 35mm

Weight: 96g

Location: Lyndhurst, NSW, Australia

Rarity of Mineral

Rare

Did you know!?
Chalcedony also forms many other pseudomorphs after organic material. A well-known example is petrified wood, in which the wood has been completely transformed into Chalcedony.