A spiffy coin. Here is some info about the range of values:
1. The date is 1700. The King of Portugal at that time was Pierre II, i.e., Peter II, Pedro II, PETRVS II, as read in the inscriptions.
2. The denomination is 4000 reis, as seen on the side with the crowned shield.
3. The catalogs report the weight at 8.05 grams. There are 31.1 grams in a troy ounce, so the coin has 8.05/31.1 = 0.259 troy ounces of gold, or probably a little less because the metal is probably not pure gold.
4. At current market levels, 0.259 ounces of gold is worth about $320 US dollars. This is called the base value (BV) of the coin. Some people call it the melt value or the bullion value.
5. Any value over BV is due to collector demand. With such an old and interesting coin, the collector premium over BV is substantial, as long as the coin has decent wear and eye appeal ratings.
6. Our picture shows two coins from the auction database. The (A) coin sold for $760 US dollars during a 2015 auction by iNumis. The (B) coin sold for $3700 US dollars during a 2015 auction by Maison Palombo. CoinQuest thanks the sellers for use of their coin photos.
7. From our picture it is perfectly clear why the (B) coin is worth more than the (A) coin. The (B) coin has no wear and knock-your-socks-off eye appeal.
8. At the low end of the price range, a 4000 reis which has been totally smashed, perhaps nicked, gouged, cleaned, or mutilated, would be worth BV, about $320 in today's gold market.
9. At the high end, a dazzling example can push retail sale price toward $4000.
10. Based on the analysis above, catalog values (which are always inflated compare to actual values), would run like this:
worn (G4): BV + $100
average circulated (VF20): BV + $500 US dollars approx catalog value
well preserved (XF40): BV + $1000
fully uncirculated (MS60 to MS70): $5000