The vast majority of trachyte produced during one hundred years of quarrying from Mt Gibraltar was sent north to Sydney. It was initially used for kerbs and gutters and can still be seen in many of central Sydney's streets. Once its durability and imposing appearance came to the attention of architects, it was used in many significant buildings and monuments. It also replaced sandstone flagging which was too quickly worn away. It could easily be considered the second most significant construction stone in Sydney, after the local sandstone. But you don't have to go to Sydney to see trachyte in use.
At the published coordinates you will find Bowral Court House. This building was constructed between 1895 and 1896 using local sandstone and trachyte quarried from nearby Mt Gibraltar. There are very few remaining significant public buildings in the Southern Highlands constructed using trachyte. In order to claim a find on this Earthcache you must visit the published coordinates and carry out some observations of the use of trachyte in this building. You can carry out all observations from the pavement outside the boundary wall.
Email me via my profile linked above, with the answers to the following questions:
1. The pillars at the corners of the surrounding wall are a good place to examine the lighter sandstone and darker trachyte in close proximity to each other. Note that this site is heritage listed so don't chip or scratch the stone. Examine both types of stone and describe them. Consider overall colour, grain size, variation in grain size and colour of individual grains.
2. Now you are familiar with both types of stone, consider the building and the surrounding wall. How would you characterise the use of sandstone and trachyte?
a) mostly trachyte, with sandstone edging
b) mostly sandstone, with trachyte edging
c) sandstone and trachyte used interchangeably
3. Which of the two types of stone is used for the fine details such as the window surrounds and the scrollwork near the peak of the roof? Why do you think this was used in those places in preference to the other type of stone?
4. Trachyte in Sydney is generally seen with one of three finishes listed below. How is the trachyte finished in this building?
a) polished - a very smooth, shiny surface
b) tooled - marks made by a chisel or cutting tool extend in straight lines across the surface of the stone
c) rock-faced - exposed block faces are left with a rough, textured surface
You may post your Found log immediately without waiting for my response. I may not contact you unless I feel your answers require clarification. If I don't receive correct answers within 7 days of your Found log being posted, I may delete your log. Please don't post answers to the questions above in your log.
First To Find honours go to: 10011010, AsTheCrowsFly' and Muppet95!