An alexandrite piece of ore (chrysoberyl rough) weighing over 2984.9 ct (597 gr) was found at the Malyshevskoye deposit's (Russia) in 2000, was valued at 175.000 USD
as an opening bid, but nobody wanted to buy it. Russian owners named it "Patriot" - a common practice for unique specimens.
After gemmologists from GOKHRAN
- the official Russian depository for precious metals and gemstones, examined the specimen, the name "Patriot" was revoked and the specimen down valued to 15.000 USD
But as David pointed out, such large pieces of rough could have value even if it doesn't have gemmy parts, as a unique specimen for the museum or private collection.