IronDigger Posted January 7, 2019 Share Posted January 7, 2019 I have had this gold /quartz specimen for a number of years....and have not been able to figure out the gold weight using the simple formula I found on the internet. For those of you willing to take up the challenge I can give you the dry weight and submerged weight in grams. I have attempted it a few times but I always come up with a negative number for total grams in specimen. Not sure if it means I have under an ounce or not. So here we go...total dry weight is 242 grams....submerged weight ..and by the way I did it properly...is 71 grams. My estimate is 24 grams ...than it ended up 1.4 ounces.. Hopefully a few of you come up with more of an accurate number... Thanks Link to comment Share on other sites More sharing options...
Walker Posted January 7, 2019 Share Posted January 7, 2019 Do you have a picture of it? Sounds like it's not just quartz an gold. Or maybe a large air pocket in it. 2 Link to comment Share on other sites More sharing options...
Jim in Idaho Posted January 7, 2019 Share Posted January 7, 2019 Yup...I get a density of 1.415g/cu.cm. That's lower than pure quartz. Jim 1 Link to comment Share on other sites More sharing options...
IronDigger Posted January 8, 2019 Author Share Posted January 8, 2019 Jim, I came up with the same density number....just the end result didn't make sense how can it be a negative number? Is it because it has a void or perhaps not all quartz? May just put it in Wink for a few weeks... 1 Link to comment Share on other sites More sharing options...
phoenix Posted January 8, 2019 Share Posted January 8, 2019 Hey IronDigger I`ve always used the formula 3.1 x the weight in water, minus 1.9 x the weight in air. With that formula you speci has minus 21.9 grams. Dave 2 Link to comment Share on other sites More sharing options...
IronDigger Posted January 8, 2019 Author Share Posted January 8, 2019 1 minute ago, phoenix said: Hey IronDigger I`ve always used the formula 3.1 x the weight in water, minus 1.9 x the weight in air. With that formula you speci has minus 21.9 grams. Dave Hi Dave, so would we say it has apprx. 22 grams of gold....? The minus got me all confused... :) Link to comment Share on other sites More sharing options...
phoenix Posted January 8, 2019 Share Posted January 8, 2019 Hey IronDigger. My bad, I didn`t multiply the dry weight by 1.9. The correct answer with my formula is minus 239.7 grams Dave 2 Link to comment Share on other sites More sharing options...
Jim in Idaho Posted January 8, 2019 Share Posted January 8, 2019 2 hours ago, IronDigger said: Jim, I came up with the same density number....just the end result didn't make sense how can it be a negative number? Is it because it has a void or perhaps not all quartz? May just put it in Wink for a few weeks... Yeah, as Walker said, must be a void, or large portion of very light rock within it. Maybe you should soak it in plain water overnight, and then do the water weight test again. If there is a void, and it fills with water, the water weight should be correct. If there is a void, and the water can get to it, you should see bubbles rising in the water. Jim 3 Link to comment Share on other sites More sharing options...
mn90403 Posted January 8, 2019 Share Posted January 8, 2019 I always use this calculator. http://desert-gold-diggers.org/gold/specgrav.htm Recently I came up with a negative weight on a specimen like you are doing with this one. I had to re-weigh the specimen more accurately making sure the wet weight was not touching any sides of a container with the water. As has already been stated, your specimen should weigh more in water than what you are reporting to us. Something is wrong if this is a host of quartz. We still haven't seen a photo of the specimen so no further help can be given. Mitchel 3 Link to comment Share on other sites More sharing options...
IronDigger Posted January 8, 2019 Author Share Posted January 8, 2019 Davsgold , thanks for the good news !! I did subtract and got the 171, where I may have messed up is the rest of the formula I will give it a shot until I get the same numbers. Looking at the piece and the amount of surface gold on it I knew it had more than 31 grams. The amount inside the rock was the mystery..appreciate your help. Link to comment Share on other sites More sharing options...
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