Possible auriferous metal

Found another chunk of metal in seawater which possibly came from a hydrothermal source. I'm totally out of acids and can't take the time to drive 330km to get more till after Xmas. Heck, I had to use a toilet bowl cleaner which has some HCL content to clean part of this lump. A visit to a local goldsmith is not feasible. If I had some conc H2SO4 and HNO3 right now, I could get a reasonably accurate idea of what it is.  Anyways, attached is a photo of the streak test done on the unglazed back of a ceramic tile.

Color: ranging from silvery-yellow to a slightly darker brassy yellow. There are some minor coppery-red patches on the surface and even smaller patches of what appears to be verdigris.
Streak: ranging from grayish-black to light silvery yellow to gold/brassy-like yellow (please refer to attached photo). The grayish-black portions will have a faint yellow glow when viewed at an angle.
Magnetism: none
Hardness: less than 5.5 on Moh scale (can be easily scratched by kitchen knife), but cannot be scratched with fingernail.
Malleability: Taps with a hammer flattens the parts I hit, no shattering.

QUESTIONS:
In the course of trying to find out what this lump is, I came across a family of metals called Tellurides. They almost fit the characteristics of this lump, except they are brittle and this lump is malleable.

1) It is possible that a member of the Telluride family combines with a chalcopyrite or some other unbrittle mineral naturally? If so, that could explain the malleability and the small parts of what appears to be copper and oxidized copper.

2) I came across a non-acid test for Tellurium at

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which instructs: "Charcoal Test.When heated on charcoal a white sublimate of TeO2 is formed which somewhat resembles antimony oxide. It is volatile and when touché with the reducing flame gives a pale greenish color to it." Is this test accurate? If so, I'll yank out the BBQ.

3) Whats a good reference book on identifying minerals in the field?

Thanks!









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http://www.thunting.com/smf/index.php/topic,19805.msg130272.html#msg130272

Understood, Steve. It's way better and easier to have the metal in hand for identification. Thanks for the info. The more I look at it, the less I think it do be a telluride too.

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http://www.thunting.com/smf/index.php/topic,19805.msg130443.html#msg130443