<p>There is no good answer to this questions.</p>
<p>All rocks contain all naturally occurring elements in the periodic table. Greater contents of an element in a rock do not necessarily translate into its abundance in the groundwater.</p>
<p>For example, uranium contents are usually elevated in granites relative to basalts. But whether this uranium can be leached out depends on how old the rock is (5 million years is young, 1500 million years is old), which specific minerals are hosting the uranium (zircon will not readily give up its uranium), the oxidation state of the groundwater (lots of organic matter will immobilise uranium in its reduced state).</p>
<p>Limestone, for example, can have very low uranium contents, but it would readily acquire uranium from fluids that contain uranium from elsewhere. It would not be easy to distinguish the two types of limestone.</p>
<p>As for silica that you mentioned in your question, it is dangerous when silica dust is inhaled into the lungs. I am not aware of any problems with silica in groundwater (and don't worry about it - it's a very insoluble element).</p>
<p>The only way to know for sure what are the levels of the various elements in different types of groundwater, is to measure them. Trying to predict their composition based on the rock types is not far from guesswork.</p>

CC BY-SA 4.0
2022-01-19T16:33:28.130Z
Thank you for your answer with lots of useful info. However, the idea about the water was more like an example. Like if I would phrase it this way instead: if I get to choose one rock to eat a pellet of as a "mineral supplement", which ones should I choose based on them having the most useful minerals at the same time as having few harmful compounds. I realize now, however, that this would probably be impossible to answer
xashm
CC BY-SA 4.0
2022-01-20T03:14:44.500Z
@xashm yes there is no good answer. Don't just pick up rocks and use them as food supplements. If you have a certain deficiency, then address that specifically with dedicated supplements. In any certain rock, the bioavailability of whatever your body requires is not guaranteed, and the rock can contain harmful and bioavailable elements.
Gimelist
CC BY-SA 4.0
2022-01-12T03:06:37.520Z
2022-01-12T03:06:37.520Z
Gimelist
<p>When talking about rocks, i.e. an aggregate of minerals, which type would be the &quot;healthiest&quot;</p>
<p>I'm <em><strong>not</strong></em> talking about some voodoo crystal-healing stuff here, just if there is any rock formation that has a relatively high number and proportion of <strong>minerals that the body needs</strong> e.g. magnesium, potassium, zinc etc that would <em><strong>leach into water (like mineral water)</strong></em> for example if you live in an area where that rock is prevalent where the community takes their groundwater</p>
<p>At the same time as having a relatively <strong>low number of minerals that the body does not need</strong> (or that would eventually also be harmful at high quantities) e.g. silica, uranium, talcum etc</p>

CC BY-SA 4.0
2022-01-11T21:22:15.757Z
Just make sure the concentration of whatever you wanting in the water is within safe limits.
Fred
CC BY-SA 4.0
2022-01-11T22:24:49.030Z
No I'm just curious about different rocks according to those criteria, water is an example
xashm
<mineralogy><rocks><minerals><groundwater>
What is the "healthiest" rock?
xashm
# What is the "healthiest" rock?

(Asked by: username_0 on 2022-01-11)

When talking about rocks, i.e. an aggregate of minerals, which type would be the "healthiest"

I'm ***not*** talking about some voodoo crystal-healing stuff here, just if there is any rock formation that has a relatively high number and proportion of **minerals that the body needs** e.g. magnesium, potassium, zinc etc that would ***leach into water (like mineral water)*** for example if you live in an area where that rock is prevalent where the community takes their groundwater

At the same time as having a relatively **low number of minerals that the body does not need** (or that would eventually also be harmful at high quantities) e.g. silica, uranium, talcum etc

**Tags:** mineralogy, rocks, minerals, groundwater

> **Comments:**
> **username_1**: Just make sure the concentration of whatever you wanting in the water is within safe limits.  
> **username_0**: No I'm just curious about different rocks according to those criteria, water is an example  

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## 1 answers

### Answer by username_2 on 2022-01-12. Score: 2

There is no good answer to this questions.

All rocks contain all naturally occurring elements in the periodic table. Greater contents of an element in a rock do not necessarily translate into its abundance in the groundwater.

For example, uranium contents are usually elevated in granites relative to basalts. But whether this uranium can be leached out depends on how old the rock is (5 million years is young, 1500 million years is old), which specific minerals are hosting the uranium (zircon will not readily give up its uranium), the oxidation state of the groundwater (lots of organic matter will immobilise uranium in its reduced state).

Limestone, for example, can have very low uranium contents, but it would readily acquire uranium from fluids that contain uranium from elsewhere. It would not be easy to distinguish the two types of limestone.

As for silica that you mentioned in your question, it is dangerous when silica dust is inhaled into the lungs. I am not aware of any problems with silica in groundwater (and don't worry about it - it's a very insoluble element).

The only way to know for sure what are the levels of the various elements in different types of groundwater, is to measure them. Trying to predict their composition based on the rock types is not far from guesswork.

> **Comments:**
> **username_0**: Thank you for your answer with lots of useful info. However, the idea about the water was more like an example. Like if I would phrase it this way instead: if I get to choose one rock to eat a pellet of as a "mineral supplement", which ones should I choose based on them having the most useful minerals at the same time as having few harmful compounds. I realize now, however, that this would probably be impossible to answer  
> **username_2**: @username_0 yes there is no good answer. Don't just pick up rocks and use them as food supplements. If you have a certain deficiency, then address that specifically with dedicated supplements. In any certain rock, the bioavailability of whatever your body requires is not guaranteed, and the rock can contain harmful and bioavailable elements.  

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