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Geology, Palaeontology & Archaeology / Re: Is this fools gold or real gold?

« on: 19/05/2018 23:06:17 »

I know nothing about how to distinguish real gold apart from fools gold ...

If you can see cubic crystals, it's not gold.

https://en.wikipedia.org/wiki/Pyrite#Distinguishing_similar_minerals

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Geology, Palaeontology & Archaeology / Re: Is this fools gold or real gold?

« on: 19/05/2018 21:32:27 »

Some tips:

- Gold is far more dense than pyrite (19.3 g/cc vs.4.8-5 g/cc).
- Pyrite is much harder than gold (6-6.5 vs.2.5-3 on the Moh's scale).
- Gold is diamagnetic, whereas pyrite is paramagnetic.
- Pyrite is much more brittle than gold.
- Gold has a gold streak, whereas pyrite has a brown-black to green-black streak.

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Geology, Palaeontology & Archaeology / Re: Is this fools gold or real gold?

« on: 19/05/2018 21:12:20 »

I'll bet my mortgage that that's pyrites (fool's gold)...

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Physiology & Medicine / Re: Does an under-active thyroid affect blood circulation?

« on: 19/05/2018 20:42:20 »

Yes, hypothyroidism does affect the heart and blood vessels.

Thyroxine, the hormone produce by the thyroid, increases heart rate and also makes the heart pump harder (increased ventricular contractility). It also reduces the systemic vascular resistance acting on the arteriolar smooth muscle cells.

At the same time, elsewhere in the body, thyroxine increases the volume of circulating blood by promoting release of the hormone erythropoietin, which increases red blood cell mass; in the kidney, the renin-angiotensin system is activated which increases sodium reabsorption - this increases circulating volume. In the vasculature, throxine promotes synthesis of nitric oxide, a hormone that relaxes blood vessels.

Thyroxine deficiency results in the reverse of all of these effects; sufferers may have bradycardia (low heart rate) and heart failure and poor peripheral perfusion. Chronic hypothyroidism can also lead to raised cholesterol levels.

Fortunately these problems can be readily reversed with simple thyroxine supplementation, which is titrated to the correct dose clinically and biochemically. But do you know for certain you have this problem?