FIMI

The Italian standard for certification is based on FIMI requisites.

What is FIMI?

Federazione Industria Musicale Italiana (FIMI)

(English translation - Italian Music Industry Federation)

As with all other regional organizations, the primary purpose of FIMI is to "protect the interests of the Italian record industry." (Wikipedia)

As of 1995, the Italian Music Industry Federation provides the official albums chart.  As of 2008, the physical singles chart was replaced with the digital downloads chart.

(Full details about charts can be found on Wikipedia)

Sales Certification

Albums

*As of 2014

Gold - 25,000

Platinum - 50,000

Diamond - 500,000

Singles 

*As of 2015

Gold - 25,000

Platinum - 50,000

Diamond - 500,000

My take away -

RIAA will always be the ultimate standard for Gold, Platinum, Multi-Platinum, and Diamond.  RIAJ will always be the eastern equivalent of RIAA.  Associations in between set their own bar.  FIMI offers an impressive standard in the Italian music industry and achieving Diamond status is truly an honor.