[Rockhounds] Streaking (WAS: Darwin, CA Pyrite RATED PG-13)

[John Siebel]

Carolyn wrote:
>> try identifying your metallic mineral by a little streaking!!!

Boy, does that remind me of my college days! What a weird fad. I could tell 
stories but I don't know if I could stay on topic without getting too lewd.

Anyway, the silver mineral in this specimen streaks brown (I had to double 
check with Julie as I am color blind). Hardness seems to be about 5ish. 
Rules out galena and arsenopyrite yes? Again, Mindat gives me these 
associated minerals. http://www.mindat.org/loc-3466.html

Where to from here?  - John

----- Original Message ----- 
From: "Carolyn Reynard" <sunstone3 at hvc.rr.com>
To: "Rockhounds at drizzle.com: A mailing list for rock and gem collectors" 
<rockhounds at lists.drizzle.com>
Sent: Friday, December 05, 2008 11:17 AM
Subject: Re: [Rockhounds] Re: Darwin, CA Pyrite RATED PG-13


> Hi John,  Not bad at all! We are having a bit of fun with this one.  Next,
> try identifying your metallic mineral by a little streaking!!!
>
> A streak test will give you the color of the mineral in powdered form.
> Firmly rub the mineral on an unglazed piece of tile.  Pyrite will give you 
> a
> greenish-black color, Galena will give you a dark gray, Arsenopyrite will
> streak black.  Also there is a difference in hardness, Pyrite is 6 - 6 
> 1/2,
> Galena a 2 1/2 -3   Arsenopyrite a 5 1/2 -6. I have added Arsenopyrite
> because it is another hydrothermal mineral.
>
> I'll take my bubbly in a glass!
> Carolyn
.com/Rockhounds/index.html