This is a golf club dated to the 1760s based on New Zealand technology [or lab work] testing the metal. The note on the “precise” date of 1760s has a margin of error +/- 40 years, which means the club could range from 1720 t0 1800.
Though there is such a large margin of error in the exact dating, this particular club (listed for bid starting over USD $1,000) does give an interesting footnote on the clubs of the era of the first golf in America:
1743 – the first shipment of golf clubs came over to America via Charleston, SC
1786 – the first golf club in America was formed, the South Carolina Golf Club, who played on Harleston Green
So, this club is an example piece of the irons used in that time. The clubs in that day were generally set as wooden-headed clubs as well as one or two irons being cast-iron-headed clubs. The use of these iron clubs was for the modern typical 5 iron to 9 iron, depending on the player’s prescribed make for the blacksmithy or cobbler or the like that fashioned the shafts and heads for the gentlemen players.
This particular iron looks rather poorly fashioned given the long metal support piece at the joint of the head and shaft, whereas the normal iron club making consisted of inserting the shaft end into the hollow of the iron head and cooling the iron in a pale of water which caused the iron to rather neatly and permanently shrink around the wooden end-piece. The shaft woods were generally ash (or apple, pear, hazel) until hickory became the new technological advance by the mid 19th century. [Related to this is that the golf club heads were either of the same/similar wood material as the shaft only out of a single block, or as was more predominantly the case, made from blackthorn, beech, or such until persimmon and even sometimes dogwood became the new technology.]
Irons were not really the most common club, though the putter was often a iron-headed club. The predominance of wooden-headed clubs of course makes sense in thinking about the origination of the game of golf from shepherds’ crooks, wooden walking sticks. But it also follows the logic of the ease-difficulty of manufacturing abilities of the time: dealing with multiple media (iron and wood) would have been a much more difficult work. Also, who wants to carry around a heavy iron club, even if you’re only playing Leith Links, which was only 5 holes?