Help With 2c Decimal Coins

I typed "1966 Australia 2 cent" into my browser search window and found the following. I don't know how old or accurate the information is but it's a starting point.

COINS WITH 'SD' (see below)
worn: less than $1 US dollar approximate catalog value
average circulated: less than $1
well preserved: less than $1
fully uncirculated: $1

You can see these are low-value coins. There are a few better dates, as follows:

COINS WITH 'SD' (see below)
1966: $3 fully uncirculated
1967: $3 fully unc
1968: $10 unc
1969: $2 unc
1986: $3 unc
1987: $3 unc
1972: $12 unc

Concerning the 'no SD' variety, it often takes a magnifier to see the tiny SD initials under the lizard. SD means Stuart Devlin, the coin's designer. If no SD appears, the coin is valuable because collectors want to add 'no SD' coins to their collections.



Typical values for 'no SD' coins run like this:

COINS WITHOUT 'SD'
worn: $1 US dollar approximate catalog value
average circulated: $10
well preserved: $25
fully uncirculated: $100

It is not clear why the SD initials are not present on some coins. It is probably 'die fill' wherein the hard-metal dies used to press out each coin get filled with greasy dirt before the mint workers can clean them out. This produces the 'no SD' variety and there are not many of them.