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1
General Discussion / Re: Dangerous minerals
« Last post by Plutonium on January 19, 2019, 10:24:54 PM »
Ah Dangerous minerals. I love them.
The crystal healing hippies love crystals that do nice things. Mine do death and destruction.

Top of the list is the Uranium and Thorium minerals. They're radioactive, so most people understand that that presents a hazard.
They also emit radon gas which is also radioactive, even more so. Their presence poses a hazard so if you collect them like I do, you need to take some special precautions. But a small piece of torbernite sitting on a shelf in a collection doesn't present much of a hazard.

The Arsenic minerals of course present a chemical toxicity.  Handing the minerals doesn't pose much of a problem, but excessive handling or heating the minerals can.

The same can be said for Mercury based minerals. Mercury salts present more of a problem and it would be wise to avoid handling them.
The Mercury salts win my vote for the nastiest.

Lead minerals are toxic too, though most people are not as afraid of lead because it's toxicity is slow and not easily recognised.
But similar caution should be used with lead minerals as with mercury and I generally would avoid letting children directly handle lead minerals.

There are a few other minerals deserve caution. Thalium minerals and Asbestos related minerals. Though in general they don't present much of a hazard as a specimen sitting on a shelf every day.

It's not hard to stay safe. Wear some disposable gloves, wash your hands, don't lick your specimens.
 


2
General Discussion / Re: 403 errors
« Last post by MakkyBrown on January 19, 2019, 10:04:23 PM »
Given up trying, was trying to post a picture in one of my galleries. Numerous attempts.
3
General Discussion / Re: 403 errors
« Last post by MakkyBrown on January 19, 2019, 09:59:57 PM »
Won't let me post a picture, multiple attempts 403 everytime.  :( 
4
Gemstone Faceting / Re: Math Formula
« Last post by MakkyBrown on January 19, 2019, 09:21:13 PM »
You'll get variation in finished stones due to girdle thickness.
5
General Discussion / Snake Catching
« Last post by Sandbagger on January 19, 2019, 08:26:45 PM »
It's weird you know, ever since I lost my job at parks and conservation, I have caught more snakes than I ever had to while I was there.

I've caught three at work in the last few months, all Eastern browns. Looks like they are all seeking shelter from the heat.

This little fellow was sitting next to the foot of one of our knife-making students on Thursday, the second time it had been spotted in as many days. Even the grinding, heavy boots and power hammers didn't scare it out of the workshop. Mind you, it was 45 degrees in there most of the day. It would take a lot to get me to go back out in the sun.

All three snakes were released a distance away from the buildings in river habitat where they will be OK.

Disclaimer: Please do not attempt this unless you are trained. (I am).

Eastern Brown snakes, are among the deadliest of the venomous snakes in the world. All it takes is one bite to kill a grown adult.

https://en.wikipedia.org/wiki/Eastern_brown_snake




Video here >>> https://www.youtube.com/watch?v=wsKDyfVFKOM


Baz.
6
Fossicking Locations / Re: Is Grabben Gullen dead?
« Last post by Sandbagger on January 19, 2019, 07:03:27 PM »
Thanks mate.

I have a question about the source of the sapphire.

If the specimens found are tiny, broken up and off larger crystals, one would assume there is a source further upstream, (Logically). Would this source be a single lode of larger stuff at a given area, or is it in the ground, broken up all the way along the rivers?

Does the erosion bring the stuff down from higher elevations, flats and surrounding catchments, or does it just wash the top off what is already there, all along the river?

Some specimens I have found in other places have a hexagonal cross section, like they are a slice from a large crystal. Where are these crystals?

I hear, "No-one really knows" all the time and think, I'm being fed a line - surely someone knows? How long have humans been mining this stuff?

Then I think, if someone does know, then surely it would all be gone?

Baz.

7
Gemstone Faceting / Re: Math Formula
« Last post by MakkyBrown on January 19, 2019, 01:44:00 PM »
I am sure you are right, MakkyBrown, but with my limited understanding of math and how I interpret your formula, I can't make it work.
Your formula:

Stone weight in ct =V/W3 *5 * SG *(Width Cubed in millimeters/1000)

V/W3 from diagram
SG = specific gravity

My interpretation (example: 6mm sapphire, design vol-factor 0.223): 0.223 divided by 1296 multiplied by 5 multiplied by 4

I am unsure about where the '5' comes from and also, I don't know whether there is a third multiplication.

The above stone should come out pretty close to a carat but no matter which way I calculate it, I can't get anywhere near that.
Please excuse my ignorance, I had no idea it would be this complex, just thought there was an easy way to reverse the calculation.
Appreciate everybody's input. Thank you.
Ok
the 5 is from 5ct in 1gram

V/W3 = 0.223
SG = 4 for sapphire
https://www.gemselect.com/gem-info/specific-gravity.php

Stone width 6mm
Stone weight in ct =V/W3 *5 * SG *(Width Cubed in millimeters/1000)
don't need the brackets
ct = 0.223 *5*4 *6*6*6/1000 = 0.96
   
 :)
8
Gemstone Faceting / Re: Math Formula
« Last post by Gemini on January 19, 2019, 11:33:14 AM »
I am sure you are right, MakkyBrown, but with my limited understanding of math and how I interpret your formula, I can't make it work.
Your formula:

Stone weight in ct =V/W3 *5 * SG *(Width Cubed in millimeters/1000)

V/W3 from diagram
SG = specific gravity

My interpretation (example: 6mm sapphire, design vol-factor 0.223): 0.223 divided by 1296 multiplied by 5 multiplied by 4

I am unsure about where the '5' comes from and also, I don't know whether there is a third multiplication.

The above stone should come out pretty close to a carat but no matter which way I calculate it, I can't get anywhere near that.
Please excuse my ignorance, I had no idea it would be this complex, just thought there was an easy way to reverse the calculation.
Appreciate everybody's input. Thank you.
9
Cabbing and More / Re: Changing Ball-Bearing on the left side of DP Pixie
« Last post by olaf on January 19, 2019, 12:14:16 AM »
Thanks for your answer!

Greetings,
Olaf
10
Trip Talk / Re: Heading to Gemtree & Harts Range
« Last post by Jamo on January 18, 2019, 10:06:49 PM »
Surprising your going there, no fern.  ;)  Awesome place to fossick wouldn't mind going back but I think in June/July. April might be ok for you mainlanders used to the heat.

Making a detour on the fern hunt. Nice to have some other pretties to play with.
Yes, the days will be warmer ... but so will the nights. Don't like being too cold, but that can usually be solved by a good fire and a warm sleeping bag.

Bucket, yes I will be at the Gemkana
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Recent Activities

Dangerous minerals by Plutonium
[January 19, 2019, 10:24:54 PM]


403 errors by MakkyBrown
[January 19, 2019, 10:04:23 PM]


Math Formula by MakkyBrown
[January 19, 2019, 09:21:13 PM]


Snake Catching by Sandbagger
[January 19, 2019, 08:26:45 PM]


Is Grabben Gullen dead? by Sandbagger
[January 19, 2019, 07:03:27 PM]


Changing Ball-Bearing on the left side of DP Pixie by olaf
[January 19, 2019, 12:14:16 AM]


Heading to Gemtree & Harts Range by Jamo
[January 18, 2019, 10:06:49 PM]


Any geologists out there? by harryopal
[January 18, 2019, 12:09:53 PM]


Areas around colac by MakkyBrown
[January 17, 2019, 08:53:22 PM]


Crystal structures by harryopal
[January 15, 2019, 04:28:00 PM]


What scales for weighing gold? by Sandbagger
[January 13, 2019, 11:41:38 PM]


Mt Gambier- South Australia Fossicking by Rusted
[January 12, 2019, 03:58:19 PM]

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