Mystery Minerals to Identify

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I got interested in rocks and geology years back but have never been good at identifying them so this is a challenge.

I got this rock grab-bag of hand specimens for Christmas, now I need to figure out what I have.
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This one is pretty easy, I don’t need a scratch test to know it is the igneous rock obsidian, a glass-like rock that is not quite a mineral because it erupts to the earth’s surface so fast it has no time to form crystals.
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I like how a bit of the matrix from the surrounding igneous rocks still adheres here top and bottom.

Thus it’s not a true mineral, lacking an “ordered atomic structure” and a “definite chemical composition”. But it is a mineraloid.

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White ‘snowflakes’ result when the unstable and quickly degrading (in geologic time) mineraloid begins to break down and crystallize.

Obsidian was quite the early hominin ‘strategic material’ for our ancestors, with its properties of toughness, denseness, hardness, easy workability and very sharp edges.

Probably the first target of human mining.

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This spall mark shows the typical conchoidal fracture of the rock: “a fracture with smooth, curved surfaces, typically slightly concave, showing concentric undulations resembling the lines of growth of a shell”.

It was a perfect rock for production of all types of hand tools and weapons for cutting, slashing, smashing and butchering.

Its chemical composition is similar to rhyolite and granite, and it is often associated with those rocks.
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I have a handle on this specimen too. It’s a phyllosilicate mica rich in lithium and aluminum known for its pink and lilac colors called lepidolite.

It’s a commercial ore of lithium with a chemical composition of KLi2AlSi4O10F(OH).
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Or else it’s a very similar colored mica mineral called Muscovite.
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Pretty sure these are geode slices, the ‘rocks with a surprise inside’. And mighty pretty too.
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The mineral lining the cavity is often a scintillating druse of tiny quartz crystals underlain by multiple bands of translucent gray and white agate. Many are lined with more spectacular treasures. Hobart M. King
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In this one few crystals are visible, it’s mostly milky translucence with inclusions.
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I feel I should know what this rock is but can’t come up with it, though I’ve seen it before.
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I want to say it’s ‘calligraphy stone’, so called. But it doesn’t quite match what I see online. I give up.
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Now I’m really over my head. Some kind of fossil? Desert Varnish? I dunno.

If anyone has an idea, or if I’ve wrongly identified some, then let me know.


Again, no clue as to what I have here, though the striated olive columnar crystals and pretty pink and white surrounding rocks should tell me something.

But I don’t know enough to know what.
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I’ve spared you the tedious description of how these rocks and crystals affect your chakra, aura, liver and lights, the first five web search results always found for any mineral.

Because you don’t believe superstitious nonsense.
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