Regardless of date or mintmark it is not rare, but it could be worth a little more depending on what caused the dot? Take it to a dealer for an assessment.
I suggest not, otherwise it would be documented in coin catalogues. The Australian 1920 "no dot" Penny is considered to be rare at any time. On a scale of 1 to 10, it is rated at a 7. If you have an Australian 1920 "no dot" Penny with a genuine minting flaw, wrap it up very carefully and take it to a reputable coin dealer for authentication and valuation.
1936 dot penny canada
An Australian 1942 Halfpenny minted in Melbourne, has no mintmark. An Australian 1942 Halfpenny minted in Perth has a dot (.) after the (Y) in PENNY (PENNY.). An Australian 1942 Halfpenny minted in Bombay has an (I) below the King's head.
The Australian 1943 Penny was minted variously at the Melbourne Mint (no mintmark), Perth Mint (mintmark is a dot after the Y in PENNY "Y.") and Bombay Mint (mintmark is an "I" under King George's bust).
There is only Supposed to be Three 1936 Dot pennies Known to Exist. Finding another 1936 Dot Penny Would make one of the biggest Impacts in Coin Collecting History. That would make it the 4th - 1936 Dot penny Proving there are more then 3! this would make it more valuable as it could rewrite History! Last Dot penny sold for 402,000$ In a Heritage Auction In New York In January 2010. A new Enthusiastic Collector From New Brunswick Canada, Has " Maybe " Found The Fourth Dot penny!
The dot is called a bindhi, and its just fashion
There are no documented occurrences available to me of a dot below the Y on a 1925 Australian Penny. Try to determine if the dot is a stray piece of metal that was pressed into the coin or, it was the result of a faulty die. A reputable coin dealer may be able to assist.
Hinduism
Australian Pennies from 1955 to 1964 inclusive were minted at either or both of the Melbourne Mint and the Perth Mint. Pennies minted at the Melbourne Mint have no mintmark. Pennies minted at the Perth Mint can be identified by a dot "." after the "Y" in PENNY, eg. "PENNY.". In other years, Perth Mint Pennies can also be identified by a dot after the "A" in AUSTRALIA, eg. "AUSTRALIA." or, a dot between the designers initials "K.G".
1956 Australian Pennies minted at the Melbourne Mint have no mintmark. 1956 Australian Pennies minted at the Perth Mint have a dot (.) after the Y in PENNY (PENNY.)
Red dot over the fore head signifies the third eye (knowledge).Symbolic of mental vision.
Its a red gem