Yellow sulphur looking mineral prt2

[jethro]

Sooo just to reinvigorate an old thread. https://www.prospectingaustralia.com/forum/viewtopic.php?id=29669 I was up on the eskdale spur on Saturday to help my dopey son & soninlaw recover their Motorbikes that they had to leave in the bush for a week after a communal brain fart last weekend. (long story but it turned out ok). After Operation KTMaha was deemed to be a success Ie they found there Bikes. I decided to go and do a bit of prospecting.
Ive been looking for a particular reef that was worked by several different companies between 1880 and 1910. said to be 6ft wide carring gold on the hanging wall for about a ft. So I found a reef crossing a track that was 6odd ft wide but couldnt find any workings. Took some grab samples and busted them up when I got home.'.... Aaand Ive got a truckload of this greenish yellow mineral with a waxy appearance that is heavy. Im wondering if it is just a limonite suodomorph. IE half way to Limonite. Hopefully goldierocks or Swright or Heatho can help. I have enough to send to someone for testing.

took a couple of pics in the rock

 

[user 4386]

It looks like a mineral forming a boxwork after a sulphide mineral that his been oxidised (weathered out). The boxwork usually follows things like cleavage planes in the original sulphide mineral. It can be many things, and can be a mixture. Some of the other (brown) mineral elsewhere in the specimen is limonite but possibly not this one. There are so many yellowish minerals and greenish minerals, and that belt through Eskdale has the most varied sulphide minerals in gold deposits in Victoria. The primary sulphides include galena, sphalerite, chalcopyrite, bismuthinite, stibnite, arsenopyrite, pyrite to name a few - and many of these have oxides that can be yellowish and greenish. Jarosite (iron sulphate) can also occur. Molybdenite can occur outside of the gold lodes. Without any chemistry, or identification of the sulphide mineral that it is after, it is pretty useless trying to identify from a photo.

 

[jethro]

Thank for the reply Goldrocks. Ive found minor amounts of what I think is the same mineral before in other veins / lodes. It is heavy in that it concentrates with the sulphides and gold, if present. Ive left the concentrates in the pan to see if they will oxidize more as they dry out. The yellow green mineral is now more orange. There was also some gold in the concentrates but not much and very fine. Ive got enough of this mineral now to do a few tests so Ill try a flame test on Charcoal and Hydrochloric acid. A few drops of Hydrogen peroxide did nothing. :/

 

[user 4386]

Thank for the reply Goldrocks. Ive found minor amounts of what I think is the same mineral before in other veins / lodes. It is heavy in that it concentrates with the sulphides and gold, if present. Ive left the concentrates in the pan to see if they will oxidize more as they dry out. The yellow green mineral is now more orange. There was also some gold in the concentrates but not much and very fine. Ive got enough of this mineral now to do a few tests so Ill try a flame test on Charcoal and Hydrochloric acid. A few drops of Hydrogen peroxide did nothing. :/

Yes, a flame test is the way to go. Sometimes one can identify the shape of the original mineral that the secondary mineral has formed from. The angle between cleavage planes preserved by the mineral can help an expert, but is very tricky.