Update 1.4 brought many new items to Stardew Valley, including the Golden Scythe. It is much more powerful than a regular scythe and allows you to collect more hay in a shorter time.
To unlock a new tool, you need to access a new mine that is located in the quarry. Inside the Quarry, look for the entrance to the mine, and start exploring it.
There is only one level in the new mine, at the end of which there is a statue with a scythe in its hands. Keep in mind that the mine is full of new enemies, so I recommend bringing some healing items with you. You will also need a good sword.
To get the scythe, make sure there is room in your inventory and then interact with the statue.
