Black glass is somewhat of a general reference. Black glass is actually naturally coloured glass which hasn’t had agents added during the manufacturing process to clear it or colour it, such as soda ash and includes all natural dark olive coloured glass through to totally black. Being a natural glass colour, finding black glass on a site is generally a good indication of age, usually pre 1880’s. As you go back to the early to mid 19th century you will find 50% of the glass used could be classed as black and this percentage increases as you go back in time to the 1st and 2nd centuries where most glass was a natural olive to black in colour.
Unfortunately here in Australia, due to our relatively young age, we are not blessed with large amounts of black glass bottles to collect like the UK and Europe, however it is still a very popular bottle category to collect, due to these bottles having such beautiful crudeness and character. We still have some rare and unique black glass finds here in Australia though, like the “Black Horse Ale” bottle (as seen above), although bottled by Tooth’s Brewery in England, was only exported to the South East of Australia for the Victorian goldfields in the 1850’s and 60’s along with South Africa and New Zealand to a much lesser extent.