The user can manipulate gold into whatever shape they want; they are also capable of turning solid gold molten and vice versa. They are able to encase people in gold. The user is also able to cover their own skin in gold for increased power, to the point where they can turn into a massive gold golem.
The fruit has no known weaknesses, aside from the standard Devil Fruit weaknesses.
Enel used one of his Devil Fruit techniques called Gloam Paddling in a similar manner to this Devil Fruit's ability. Coincidentally, while Enel can used this technique to reshape any object made of metal, he used his golden staff and the gold on Ark Maxim.
However, whilst Tesoro is capable of manipulating solid gold like it is liquid or semi-solid, Enel's ability requires him to melt, forge and then cool to do so. This is apparent by how the manipulated gold is in contact with the Straw Hats, but they weren't experiencing any burns, while when Luffy experienced burns when fighting against Enel.
This Devil Fruit ability bears similarity to the mythical Midas Touch (also known as the Golden Touch) from Greek mythology, where a king gained the power to turn to gold whatever he touched, even unwillingly.