Lanzini joined the Hammers on loan from Al Jazira Club as a relative unknown, but he has made an immediate impact at Upton Park.
The Argentine attacking midfielder has forced his way into Slaven Bilic's starting line-up, and Gold was impressed by the 22-year-old's display against Sunderland in the Hammers' most recent outing.
"I'm sure all the fans who travelled up to the Stadium of Light would have been impressed once again with the performance by Manuel Lanzini," he said.
"I know he is nicknamed 'The Jewell' and to say he is a gem is very appropriate at the moment!
"He has incredible skills, but has a lot more to his game as well. He can tackle, pass the ball and has already shown that he can score goals.
"We have an option on him at the end of the season and you need to see him over the whole year and see someone perform at this level on a consistent basis.
"But if he keeps putting in the displays that we are seeing at the moment, then the manager will keep picking him."
West Ham drew 2-2 with Sunderland at the Stadium of Light, extending their unbeaten run away from home this season to four games.
The Hammers have collected wins at Manchester City, Arsenal and Liverpool, and Lanzini has been at the heart of most of those successes.
Outside of the club, Lanzini's impact has largely been overshadowed by the performances of Dimitri Payet, who has stolen a lot of the headlines, but at Upton Park he is quickly becoming a fans' favourite.
Lanzini's next opportunity to impress will come in the Hammers upcoming match against Crystal Palace, which takes place after the international break.