Ancient Coin Appraisal Please!

Your best bet is to check prices realized of comparables. Most major auction houses have this info available online.

It's a Gold coin ?

In my opinion, it is difficult to answer your question for these reasons:

1. This is one of only two specimens of this coin that have graded this high at NGC. "Top pop" coins have notoriously volatile prices.

2. World coins in general are moving up in value, based on anecdotal evidence of almost every world collector on the forum. So historical results from auctions of several years ago may be less relevant than one would hope.

BUT, by chance, the other MS-63 example of this coin came up for auction at STack's in AUgust 2018, and did not get the opening bid of $3,000 U.S.
https://www.numisbids.com/n.php?lot...lot&sid=2677

As mentioned by @kushanshah, places where you can do research for "comparables" are http://www.coinarchives.com which gives selling prices from certain recent auctions, or http://www.acsearch.com which is more comprehensive, but does not give prices realized unless you pay (if you are buying 5 figure coins, you may want to spring for the paid subscription)