Weird question time!

Aerotan

So, I'm looking for either a semi-precious to precious or a highly useful metal that has the following properties:

1) can be found on or near the surface

2) can be worked with medieval technology

3) rare enough that a peasant would assume it to be a different metal

4) unique enough that someone with trade experience can recognise that it is NOT that metal.

5) uncommon enough that it would be plausible for that same person to not be able to identify it completely.

6) common enough that once its value is discovered it is not prohibitively expensive to find/extract.

Essentially I'm looking for a catalyst that's going to end up destroying a nearby village, boosting a feudal lord's prestige or war capabilities, and shattering the balance of power in an area.

Elanorwen

Iron and Nickel sound like they could fit the bill. Meaning they 'look' similar enough to confuse someone that doesn't know about the two, while being different enough that a knowledgeable person might figure them out. Whether Nickel has much medieval application, I haven't looked... but I'm sure some googling will discover such information.


EDIT: Never mind. Apparently, Nickel has been used as far back as 3500 BCE

EDIT2: It might have been closer to Silver, too, which would fit the bill at a better rate. People thinking they're getting a precious metal, but not exactly. To quote wikipedia:

Because the ores of nickel are easily mistaken for ores of silver, understanding of this metal and its use dates to relatively recent times. However, the unintentional use of nickel is ancient, and can be traced back as far as 3500 BCE. Bronzes from what is now Syria have been found to contain up to 2% nickel.^[24] Further, there are Chinese manuscripts suggesting that "white copper" (cupronickel, known as baitong) was used there between 1700 and 1400 BCE. This Paktong white copper was exported to Britain as early as the 17th century, but the nickel content of this alloy was not discovered until 1822.^[25]

Daraius

Omg your neighborhood must be bonkers.

Everiine

Unobtanium! Phlebotinum!

Aerotan

It'll make sense in context. I'm not going to jump from 'ooh pretty' to 'oh God why'. >.>

Tarkenton

Saltpeter?

Aerotan

Elanorwen said:

Iron and Nickel sound like they could fit the bill. Meaning they 'look' similar enough to confuse someone that doesn't know about the two, while being different enough that a knowledgeable person might figure them out. Whether Nickel has much medieval application, I haven't looked... but I'm sure some googling will discover such information.


EDIT: Never mind. Apparently, Nickel has been used as far back as 3500 BCE

EDIT2: It might have been closer to Silver, too, which would fit the bill at a better rate. People thinking they're getting a precious metal, but not exactly. To quote wikipedia:

Because the ores of nickel are easily mistaken for ores of silver, understanding of this metal and its use dates to relatively recent times. However, the unintentional use of nickel is ancient, and can be traced back as far as 3500 BCE. Bronzes from what is now Syria have been found to contain up to 2% nickel.^[24] Further, there are Chinese manuscripts suggesting that "white copper" (cupronickel, known as baitong) was used there between 1700 and 1400 BCE. This Paktong white copper was exported to Britain as early as the 17th century, but the nickel content of this alloy was not discovered until 1822.^[25]

That'll do it, I think! I can even come up with a pseudo-plausible way to determine that it's nickel and not silver without resorting to a crucible by use of its ferromagnetic properties.