Different Specific Gravity Tests.

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dunollyman

stephen
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how can you tell the % of gold in your specimen's? Got a couple now and have no idea how to tell and I don't want to destroy them :eek:
 
I am setting this thread up for another forum member, Jungles, but it hopefully becomes a reference for any other member wishing to find out the info.

Mostly I am searching through lots of different threads on PA and copying the links to the one place (now that I have done this there actually isn't much here :eek: )

Anyone else want to add in your favorite method please go for it.

This from Heatho http://johnbetts-fineminerals.com/jhbnyc/articles/specific_gravity.htm

From over on the DP forum - a link to another website. http://www.desert-gold-diggers.org/gold/specgrav.htm

From a Google search - http://www.gold-prospecting-wa.com/gold-in-quartz.html

Youtube Vid - https://www.youtube.com/watch?v=GF4NqIYh6zg

Hopefully this gives people a start.

Note - these are for calculating the SG of gold in quartz. Gold in iron and other rock/minerals will be different. Again, if you have a workable method for these please link them in :Y:
 
Thanks for this info, the first method is by far the least complicated, probably not super accurate but accurate enough for most peoples purposes.
 
How would I go about doing this test on a large quartz rock about the size of a car wheel?
 
You wouldnt.
Does your quartz rock have visible gold in it?
 
Some time ago I created a Series on identifying minerals blog, so that people would ask their questions on identification at one site, where I could go regularly to provide answers (since I am a mineralogist in part)

I realised then that most people did not know the process of systematically identifying minerals, so I also posted the following Series on identifying minerals which discussed this in detail and includes specific gravity (part 8):

Series on identifying minerals - part 1
(1) External appearance
(2) Specific gravity
(3) Hardness
(4) Fracture
(5) Cleavage
(6) Other physical properties
(7) Colour
(8) Streak
(9) Lustre
(10)Transparency
(11) Other optical properties
(12) Heat conductivity
(13) Other physiological properties
(14) Taste
(15) Magnetism
(16) Chemical properties
(17) Expensive laboratory tests

Series on identifying minerals - part 2 HARDNESS

Series on identifying minerals - part 3 VIEWING YOUR MINERAL

Series on identifying minerals - part 4 STREAK

Series on identifying minerals - part 5 IDENTIFICATION TABLES

Series on identifying minerals - part 6 MAGNETISM

Series on identifying minerals - part 7 FLAME AND BEAD TESTS

Series on identifying minerals - part 8 SPECIFIC GRAVITY

You can easily search them under my name - it includes specific gravity. Just one comment - sometimes too many alternative articles on one limited topic can confuse rather than help.

You will also find discussion of "fluorescence" under my name (either that or "ultraviolet")
 
Here is my uv post

05 December 2016 05:00 pm
I just checked and ruby is one of the few minerals that you might get a reasonable response from with that torch (ie some rubies, not all). I see some torches are 9W - that would be much better, and one with a range of say 400-300 nm would make about 70% of fluorescent minerals fluoresce, but with a range 400-280 nm almost any florescent mineral will fluoresce.

B5MECH - there are two different issues (I work with UV light):

(1) wattage - is it powerful enough? So yes, if you can use it inside in a perfectly dark room, close to the specimen, 4W will probably be adequate for some minerals that can flouresce in the short wavelength range that torch has.

(2) wavelength - will it fluoresce at all? This is important, for example, a ruby may fluoresce around 400 nm (few minerals will though) but a mineral like scheelite will not give any fluorescence whatsoever, no matter how high the wattage of your lamp. It has nothing to do with a weak or strong response, but with whether you get any response at all - not how well will it fluoresce, but CAN it flouresce AT ALL at that wavelength. Any particular mineral has to have light of a certain wavelength shining on it before it can fluoresce at all (fortunately it can be a bit of a range of wavelength), and the wavelength is different for different minerals. The problem is that people buy a torch and shine it on a particular mineral and it fluoresces and say "great, it works well" - but they don't realise that it is of limited range of wavelength that doesn't work for other minerals. Anyway, good luck.

In the list below, lw usually means in the range 400-315 nm, sw in the range 315-280 nm (and should only be used with protective goggles), The torch you got just barely scrapes into the edge of the lw range and not at all in the sw range.

Ultraviolet Fluorescence Chart

Abbreviations used in this chart:

lw long wavelength fluorescence
sw short wavelength fluorescence
The underlined section for some species and varieties (where applicable) indicates the general fluorescence encountered most often. Additional colors are also included. This does not mean, however, that all stones of a particular species or variety will show the fluorescence indicated for that stone.

FACTORS THAT MAY CAUSE DIFFERENCES, IN FLUORESCENCE:

Chemical impurities
Matrix and / or other foreign materials combined in or on this material.
Strain in the structure of the material
Isomorphous replacement

Please-note that it may be necessary to raise the stone up to the ultraviolet unit itself to obtain the required intensity of ultraviolet radiation necessary to produce the fluorescence indicated for a particular stone.

Amber None to yellowish green to orangey-yellow (lw) (lw works best). Also may fluoresce white, yellow, green or blue (lw), Fluorescence generally weaker under sw.
Beryl Emerald: (lw works best) none but may fluoresce weak orangey-red to weak red in very fine colors (lw and sw).
Oiled emerald: Oil shows yellowish to orangey-yellow(lw); weaker to non(sw). Oil will be noted in fractures.
Aquamarine: None
Blue Beryl: Green (sw).
Colorless: None to pale yellow or pink (lw and sw).
Golden: None.
Morganite: None to weak light red to violetish red (lw and sw).
Red: None
Synthetic Emerald Most synthetic emerald fluoresces a dull brick red (lw and sw) (lw works best). Some Gilsons fluoresce a weak to moderate orangey-red (lw and sw) to a moderate yellowish green (lw and sw). Gilson Group-III is inert.
Chalcedony All varieties: Generally inert (lw and sw); however, some may fluoresce a weak to intense yellowish green (lw and sw).
Chrysoberyl Alexandrite: None to weak red (lw and sw).
Yellow and greenish yellow: None to yellowish green (sw).
Other colors: Generally inert.
Coral White: None to weak to strong bluish white (lw and sw).
Light and dark shades of orange, red and pink: None to orange to pinkish orange (lw and sw).
Ox blood: None to dull deep red (lw and sw).
Corundum Burma ruby: Strong red (lw); moderate red (sw)
Ceylon ruby: Strong orange-red (lw); moderate orange- red (sw).
Siam ruby: Weak-red (lw); weak red to none (sw).
Pink sapphire: Strong orange-red (lw); weak orangey-red (sw).
Orange sapphire: None to strong orange-red (lw). Ceylong yellow sapphire: Moderate orange-red to
orange-yellow (lw); weak red to yellow-orange(sw). Green sapphire: None.
Ceylon blue sapphire: Moderate to strong orange to red (lw); weaker (sw).
Violet and alexandrite-like sapphire: None to moderate to strong red (lw); weaker (sw).
White sapphire: None to weak to strong orange to orange-red (lw and sw).
Brown sapphire : None to weak red (lw and sw). Black sapphire: None.
Colorless sapphire: Orange-red to red to orange (lw and sw).
Blue (dark) sapphire: None to moderate red (lw and sw).
Synthetic Corundum Synthetic ruby (flame fusion): Very strong orangey-red(lw); moderate to Strong orangey-red (sw).
Synthetic ruby (flux fusion): Strong orangey-red (strong, but not quite as strong as flame fusion or highly fluorescent natural material) (lw); orangey-red fluorescence generally stronger than natural, but some material may show zoned area of blue and /or bluish over tint on orangey-red fluorescence (sw).
Synthetic orange sapphire: Very weak orange to red (sw).
Synthetic yellow sapphire: Very weak red (sw).
Synthetic green sapphire: Weak orange (lw); dull brownish red (sw).
Synthetic blue sapphire: Weak to moderate chalky blue to yellowish green (sw).
Synthetic violet sapphire: Strong red (lw); greenish blue (sw).
Synthetic alexandrite-like sapphire: Moderate orange to red (lw and sw); may fluoresce red (lw), mottled blue (sw).
Synthetic colorless sapphire: None to weak bluish white (sw).
Synthetic brown sapphire: None to weak red (lw and sw).
Synthetic pink sapphire: Moderate to strong red (lw); pinkish violet (sw).
Diamond May fluoresce all colors with the exception of violet. General fluorescence is weak to strong blue (lw and sw).
Feldspar Albite: None to very weak brownish red (lw and sw).
Amazonite: None to weak yellowish green (lw). Oligoclase (sunstone): None to weak mottled white (lw and sw).
Transparent yellow orthoclase: None to weak reddish orange (lw and sw).
Orthoclase (moonstone): None to blue (lw); orange (sw). May fluoresce weak pink (lw and sw).
Transparent labradorite: None to weak blue (lw).
Garnet All species and varieties are inert with the exception of:
Transparent green grossluarite: None to moderate red (lw and sw).
Transparent colorless groosularite: None to weak orange or green (sw).
Ivory Weak to strong bluish white (lw and sw).
Jadeite Light green: None to weak white (lw).
Light yellow: None to weak green (lw).
White : None to weak yellow (lw).
Light violet: None to weak white (lw).
Some color-treated lavender: Weak to moderate orange (lw); weaker (sw).
Dark colors: Virtually inert.
Jet Inert.
Lapis Lazuli Generally inert; may fluoresce weak to moderate green or yellowish green (sw). The calcite inclusion may fluoresce pink (lw)
Malachite Inert
Nephite Inert
Opal Body color black or white: None to white to moderate pale blue, green or yellow (lw and sw); may phosphoresce.
Common opal or hyalite: None to strong green or yellowish green (lw and sw); may phosphoresce.
Fire opal: None to moderate greenish brown (lw and sw) ; may phosphoresce.
Pearl Natural: None to strong blue, yellow, green or pink (lw and sw).
Cultured: None to strong blue, yellow, green or pink (lw and sw).
Black pearl: Natural - none to strong red (lw); some may fluoresce light pink, mottled pink and white.
Dyed black: inert to weak white (sw).
Peridot Inert.
Quartz Green aventurine: None to weak grayish green (lw and sw).
Red dyed quartzite: Weak to strong red (lw and sw).
Rose quartz: None to weak red (lw and sw).
All other varieties: Virtually inert
Shell White: None to moderate blue to greenish white (lw and sw).
Tortoise shell: All but dark areas dull bluish green (lw and sw).
Spinel Red, orange and pink: None to weak red to orange-red (sw); weak to strong red and orange (lw).
Near colorless (rare): None to moderate orange to orange-red (lw).
All other colors: Virtually inert.
Synthetic Spinel Colorless: Moderate to strong chalky blue (sw); may fluoresce weak green (lw) and strong greenish blue (sw).
Light blue: Weak to moderate orange (lw); chalky blue (sw).
Medium blue: Strong red (lw); strong bluish white (sw).
Dark blue: Strong red (lw); strong mottled blue (sw).
Light green: Strong yellow (lw).
Dark green: Strong violetish red (lw); strong greenish white (sw).
Alexandrite like: Moderate dull red (lw and sw).
Yellowish green: Strong yellowish green (lw and sw).
Red: Strong red (lw).
Pink: Inert.
Topaz Colorless: None to weak yellow (lw).
Red: Weak brownish Yellow (lw).
Yellow: Weak orange yellow (lw).
Blue: None to moderate yellow (lw).
Brown: Weak orange-yellow (lw).
Pink: Moderate greenish white (sw).
Tourmaline Pink: None to very weak red (lw and sw).
All other colors: Virtually inert.

To quote one site that sums it up well:

"First things first. A "black light" will not work for most fluorescent minerals. Blacklights are long-wave UV. They are usually un-filtered. They are also cheap. Blacklights will make your laundry fluoresce, but they're not much good for most minerals. Do yourself a favor and take the $20 you were going to spend on a "blacklight" and put it toward a good mineral light. (A 4-watt, by the way, is not a good mineral light."

I just checked and the crash in the Australian dollar over the last few years has much more than doubled the price of lamps, so that something that is both sw and lw and with a filter (but only 4W and therefore needs complete darkness) is $180-200. So my advice is pretty useless for most people I guess (but then blacklight torches are mostly just as useless wink

e.g.

https://www.scientrific.com.au/product.php?p=1819

http://www.prospectors.com.au/p-10799-u -lamp.aspx

Robert Benchley...
I have kleptomania, but when it gets bad, I take something for it.
 
A hell of a lot of info for the bloke to get his head around GR...and you post some brilliant and handy stuff and I thank you for that.
But, I dont think he was enquiring about the specific gravity of gold. I think the dude wanted to know how does he dangle a specimen the size of a car wheel in a pot of water to get the wet weight and what size scales to use to get the dry weight so he can work out how much gold he has in his particular car wheel size lump of rock.
 
madtuna said:
A hell of a lot of info for the bloke to get his head around GR...and you post some brilliant and handy stuff and I thank you for that.
But, I dont think he was enquiring about the specific gravity of gold. I think the dude wanted to know how does he dangle a specimen the size of a car wheel in a pot of water to get the wet weight and what size scales to use to get the dry weight so he can work out how much gold he has in his particular car wheel size lump of rock.

Yes, that is what my section on specific gravity discusses - I don't see any mention of :playful: car wheels etc. In fact I don't see mention of a specific SG identification issue. And of course specific gravity is no use for identification on most large specimens unless they are unusually pure.

But yes, you can do exactly the same thing if you want e.g. to determine the number of ounces of gold in a gold-quartz specimen (I have done it on specimens containing up to 400 oz of gold in quartz - e.g. for Sovereign Hill). All the same approach, although I also give a quicker, simplified method for identifying small, pure mineral specimens.

And I summarised what I covered so the topic headings are in one place - one only has to go to the topic one wants to find out about, not read a book......many of the individual topics covered come up again and again in questions and it is quicker to send a person there BEFORE I start re-inventing the (car?) wheel - otherwise repetition becomes a bit time-consuming for me.
 
Read his post....how do I do a specific gravity test on my lump of quartz the size of a car wheel
 
madtuna said:
Read his post....how do I do a specific gravity test on my lump of quartz the size of a car wheel
I was responding to Northeast who said "Anyone else want to add in your favorite method please go for it", and had not seen the date on it. I had not seen Makerei's subsequent one-liner and was not responding to it - but what difference does size make (said the actress to the bishop)? :(

I won't waste further time on it then.
 
Hey madtuna,

Just a few days ago I was showing a bloke pictures of a 5oz speccie which had 63g of gold in it according to my specific gravity test....

His only question was, what scales did you use? I went to the car and got out my 200g gold scales at which he laughed and pulled up a picture on his IPad of a speccie hanging off a set of bathroom scales into a half barrel....

Bit over 5kg of gold.... and where I use a silver three pence for scale he used a newspaper...

True Story happened on Friday last week..
1605614396_600c7eaf-9b6e-4498-b960-12e07c0bf6bb.jpg
 
Makarei said:
Yes it has gold in the quartz rock in multiple places. Maybe it is easier to break it up into smaller pieces for the test.
Makarei - what is the purpose of what you are doing - what answer is it that you want to achieve?
 
well I broke off a small size of quartz rock it is 131.13g on scales and the wet weight using the above dangling in water not touching sides etc give a weight of 111.04g so now need to work out gold in the broken off piece.
 
Makarei said:
well I broke off a small size of quartz rock it is 131.13g on scales and the wet weight using the above dangling in water not touching sides etc give a weight of 111.04g so now need to work out gold in the broken off piece.
So there is a lot of visible gold in your rock (percents)?
 
in the small piece that broke off its 90% visible. In the large rock about 40% visible over the entire piece as its in clusters.
 
You have a problem we all would love to have. :Y:

Doing a basic SG test on a chunk the size of a car wheel will have it s problems eg..big accurate scales, dangling the bloody thing in a pot big enough etc
Id be crushing the bloody thing!

Do you have access to a multi meter? If so picking random points of visible gold on different parts of your specimen, is it connected?
 

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