quartz/gold specimen

[padego]

Hi, I'm hoping someone can help me, this has come to me with some some other crystal specimens and I really have no idea as how to value it. I've searched about the internet with little success so I'm asking if someone out there can point me in the right direction and/or offer his or her's opinion...

Many thanks in advance

padego

 

[martyn111]

The value of your specimen will be in excess of its gold content to a specimen hunter / collector.
Below is an example of a method to determine the gold content of the quartz.
If you follow the instructions given and plug your numbers into the equation you can get an idea of the weight of gold and use that as an absolute minimum value.

The measurement we really need to find is volume and this can easily be done if you have a digital scale. Take a glass or cup that is big enough to hold the rock and fill it with water so that the rock will easily be covered with water when placed in the vessel. Tie a thin piece of string around the rock such that it can be suspended in the water in the vessel so that it is not touching the bottom nor sides and is fully submerged. Now place the vessel with water without the suspended rock inside and weigh. Now add the suspended rock and determine the increase in the weight on the scale. This can either be done by zeroing out (tareing) the scale after the first measurement or by subtracting the first weight from the second. This number represents the volume of the rock in cubic centimeters since while the rock is suspended it is displacing an equal volume of water and mimicking its density which is 1 gram per cubic centimeter. Therefore the increase in the weight in grams on the scale equals the volume of the rock in cubic centimeters. when you get this number it is easy to plug into a formula for determining a fairly accurate estimate of the gold content. A piece of quartz of equal size (33.3 cubic centimeters) should weigh 88.25 grams since quartz has a density of 2.65. The formula for determining gold content in a quartz matrix is: 3.1 x weight of rock in water minus 1.9 x weight of rock in air. If there are minerals in the rock heavier than quartz like iron oxide then the estimate will run high. From past experience I tend to think this formula runs a bit high anyway and that the first number should be between 3 and 3.05.

 

[padego]

Thank you for this!

 

[shaftsinkerawc]

Pictures from all sides is beneficial from a buyers perspective. Also since you said it came to you, how did you determine that it is a quartz matrix versus a calcite matrix? Looks great. awc

 

[padego]

Good question, I just assumed it was quartz....
Here's a couple more.

 

[Williams55]

your pic is very nice but i can't understand what is this...