Witwatersrand basin

[🔥 fire and water 💦]

Greetings everyone..
Hopefully the images that I post will be adequate for everyone's viewing.
I found this specimen(887g), roughly the size of 2 packs of cigarettes ontop of each other, from a surface exposed piece of black reef in the Witwatersrand basin area, untouched or mined, most of the reef is slightly underground and full of black crystal which has obsidian properties, super sharp, cuts like a razor, even worse, lol.
Gold, platinum, palladium, rhodium and silver mine shafts surround the area which are currently active.
Please share your thoughts on this or/and experiences.
Looking forward to hearing from you guys..

 

[Alondro]

It is a rock. From images alone, it's impossible to tell anything. I've seen plain old limestone weathered exactly the same way, as well as certain types of basalt.

 

[🔥 fire and water 💦]

It is a rock. From images alone, it's impossible to tell anything. I've seen plain old limestone weathered exactly the same way, as well as certain types of basalt.

This is like precipitate and non magnetic balls and bits of metal that's been compressed(if you will) together. I crushed a piece as much as I could, gave it nitric acid treatment and after several rinses and acid treatments put it into aqua regia and i precipitated these 2 powders from the solution. Silver precipitate I separated mostly with nitrate and filtering

 

[🔥 fire and water 💦]

Thank you for taking the time to read through my post

 

[🔥 fire and water 💦]

Would

It is a rock. From images alone, it's impossible to tell anything. I've seen plain old limestone weathered exactly the same way, as well as certain types of basalt.

Can limestone or basalt have such a high density though? That piece is the size of my palm and weighs almost the same as a litre of water

 

[Shark]

Without an assay there isn’t much to go on.

 

[Alondro]

Would

Can limestone or basalt have such a high density though? That piece is the size of my palm and weighs almost the same as a litre of water

uhm, a rock the size of one's palm can be much heavier than a liter of water. A liter of water is one kilogram. It's 1000cm
³
at a density of 1g/cm3. That's a cube 10cm x 10 cm x 10cm. One side has an area of 100cm
²
. Which fits neatly into one's palm. My palm's surface area is about 15cm x 10cm, or 150cm2. So to find a rock that size that weighs about as much as water.... you're looking at limestone's density!

 

[goldshark]

uhm, a rock the size of one's palm can be much heavier than a liter of water. A liter of water is one kilogram. It's 1000cm
³
at a density of 1g/cm3. That's a cube 10cm x 10 cm x 10cm. One side has an area of 100cm
²
. Which fits neatly into one's palm. My palm's surface area is about 15cm x 10cm, or 150cm2. So to find a rock that size that weighs about as much as water.... you're looking at limestone's density!

Both Limestone and Basalt can have a specific gravity higher than Quartz, depending on type. The first picture you posted, looks like vesicular Basalt, with an ash coating on the outside ( white ). Power wash it off, and see if it turns mafic ( dark ).

 

[🔥 fire and water 💦]

uhm, a rock the size of one's palm can be much heavier than a liter of water. A liter of water is one kilogram. It's 1000cm
³
at a density of 1g/cm3. That's a cube 10cm x 10 cm x 10cm. One side has an area of 100cm
²
. Which fits neatly into one's palm. My palm's surface area is about 15cm x 10cm, or 150cm2. So to find a rock that size that weighs about as much as water.... you're looking at limestone's density!

What you are saying there makes thorough sense, however will limestone contain gold, silver, ruthenium, palladium, rhodium and copper? Xrf reading gives quantities of 20% gold, 28%percent copper, 32% silver, I can't remember the rest of the quantities. When I know on the specimen with a hammer lightly its appearance changes and becomes a silver metal.

 

[🔥 fire and water 💦]

What you are saying there makes thorough sense, however will limestone contain gold, silver, ruthenium, palladium, rhodium and copper? Xrf reading gives quantities of 20% gold, 28%percent copper, 32% silver, I can't remember the rest of the quantities. When I know on the specimen with a hammer lightly its appearance changes and becomes a silver metal.

*Knock

 

[Yggdrasil]

What you are saying there makes thorough sense, however will limestone contain gold, silver, ruthenium, palladium, rhodium and copper? Xrf reading gives quantities of 20% gold, 28%percent copper, 32% silver, I can't remember the rest of the quantities. When I know on the specimen with a hammer lightly its appearance changes and becomes a silver metal.

Is this the only rock you have?

 

[Alondro]

What you are saying there makes thorough sense, however will limestone contain gold, silver, ruthenium, palladium, rhodium and copper? Xrf reading gives quantities of 20% gold, 28%percent copper, 32% silver, I can't remember the rest of the quantities. When I know on the specimen with a hammer lightly its appearance changes and becomes a silver metal.

Do not believe XRF readings when they're that high. If the machine is not properly calibrated for the material, it will give outrageously inaccurate results. That machine is claiming this material is 80% metal alloy. It would be very dense in that case, likely somewhere around 10x the mass of the same volume of water, and almost certainly not natural. How such a material would com to exist outside of being somehow lost by a previous smelting operation in the area is beyond me. And it would be a very sloppy operation that would leave large blobs of highly valuable alloy lying around.

 

[galenrog]

What you are saying there makes thorough sense, however will limestone contain gold, silver, ruthenium, palladium, rhodium and copper? Xrf reading gives quantities of 20% gold, 28%percent copper, 32% silver, I can't remember the rest of the quantities. When I know on the specimen with a hammer lightly its appearance changes and becomes a silver metal.

Inaccuracy of XRF devices on ores and rocks has been discussed on this Forum numerous times. I suspect that the device used has a precious metals library loaded rather than the geochem library necessary. Your device is making guesses based on the library installed. Frequently, arsenic is identified as iridium and, less frequently, rhodium or other similar metals.

An XRF with a geochem library loaded is an excellent tool for determining where target metals or minerals may be in and ore face, but only by an experienced operator.

My advice? Assay. Leave the XRF to analyze metal alloys.

Time for more coffee.

 

[anachronism]

What you are saying there makes thorough sense, however will limestone contain gold, silver, ruthenium, palladium, rhodium and copper? Xrf reading gives quantities of 20% gold, 28%percent copper, 32% silver, I can't remember the rest of the quantities. When I know on the specimen with a hammer lightly its appearance changes and becomes a silver metal.

For context your gun percentages are percentages of the elements it sees and can recognise within the tiny area it shoots. That means if the applicable elements make up 2% of the overall material and your gold is 20% of that then your gold content is in reality 20% of the 2% which is 0.4%

Galenrog is spot on - whilst these guns are very useful for metal alloys, there are too many variables that come into play when mixed materials are involved. For context I learned this myself the hard way.

 

[Jakes.vdv]

This is like precipitate and non magnetic balls and bits of metal that's been compressed(if you will) together. I crushed a piece as much as I could, gave it nitric acid treatment and after several rinses and acid treatments put it into aqua regia and i precipitated these 2 powders from the solution. Silver precipitate I separated mostly with nitrate and filtering

Hi Ryan

Just out of curiosity. How certain are you that your precipitate is Silver Chloride? Does it change colour in sunlight?

I grew up on the Witwatersrand. But I live in KZN now.

 

[SeRKaN PGM HuNTeR]

Pulverise that rock until it becomes zero micron, melt it at 1000 degrees using silver metal using a flux recipe, if there is metal, it will collapse to the bottom, why I said silver because I watched an applied video on a channel "mbmmllc" that platinum group metals attract the best silver, you can get a basic idea by examining the videos here.

Regards

 

[Yggdrasil]

Pulverise that rock until it becomes zero micron, melt it at 1000 degrees using silver metal using a flux recipe, if there is metal, it will collapse to the bottom, why I said silver because I watched an applied video on a channel "mbmmllc" that platinum group metals attract the best silver, you can get a basic idea by examining the videos here.

Regards

That is almost true, but metals like Rhodium are not very fond of Silver, better use Copper or best would be Gold if the price was not that high.