The RIAA counts each disc individually in multi-disc sets, therefore this 8 times platinum award is the equivalent of a 4 times platinum award for a single cd release, four million copies sold. The award shown is “Presented to Karen Glauber to commemorate the sale of more than 8,000,000 copies of Virgin Records cassette and c.d. “Mellon Collie And The Infinite Sadness”.”
Info from RIAA.com:
“The RIAA® Gold® and Platinum® Awards program was launched in 1958 in an effort to create a standard by which to measure sales of a sound recording.
In the beginning, there was only a Gold® album award for the sale of 500,000 copies. As the industry grew, other awards were developed. The Platinum® award (1,000,000 sold) was created in 1976 and with the advent of the compact disc and the subsequent increase in sales, the Multi-Platinum™ award was created in 1984.
On March 16, 1999, the RIAA® launched the Diamond® Awards, honoring sales of 10 million copies or more of an album or single.”