What mineral is this?

Question

I have a transparent mineral that I cannot identify which looks colorless in direct light but has a very pale light blue tint against white surfaces. It looks very much like Goldquarryite however, unlike Goldquarryite it fluoreses a bright whitish blue under long wave UV. It has a hardness greater than calcite but softer than fluorite. I only have fragments of about 1.5cm long so I'm uncertain of the actual shape of the crystal but I can see some mica like layering on one of the flat surfaces, and steps can be seen in the fracture on one of the specimens. One specimen is slab shaped and the other is a chunk with a vague, somewhat stepped tetrogonal shape.. Both specimens are clear enough to read through yet there are many internal faults and some internal "rainbowing" as is sometimes seen in quartz. It was found in California amongst white landscaping rock which was primarily calcite. The mineral in question does not bubble in acid and is not calcite.

I did test it with a proper acid so it's not calcite.
It's too soft to be quartz or sodalite. It's harndess is somewhere around 3.75 mohs.

I have a sample of baryite that it does scratch but I think it's atypical baryite because it doesn't fluorese.

I think I'm kind of leaning towards fluorite even though it doesn't scratch the polished sample I have. The samples, though different colors, emit the same color under long wave UV and fluorite is a very varied mineral and harndess can vary a few fractions of a point.

Answer 1

If the mineral is clean and free from oils it should not flouress unless its calcite althought that doesnt always happen. So without it reacting to the acid, you maybe contradicting yourself. I suggest using a light detergant and cleaning the sample again to remove any traces of potential 'oils' that could be on there.

Answer 2

Based on the association and apparent lamellar morphology, I'd be thinking celestite, barite, or anhydrite. Are there any other sulphates around (like gypsum)?

None of these ought to fluoresce, so I'm not sure what's going on there, possibly there's some fluorite present too, which is reasonable.

Good luck!

Answer 3

It could be sodalite. Your best bet would be to have it thin sectioned and then petrographic analysis could be performed with a polarizing scope for better diagnostic analysis



Added:
I wish my mineralology book was at home, but it is at work, but, I might have found one mineral that fits... celestite

Here is the definition:

mineral appearing in blue-tinged or white orthorhombic crystals or in fibrous masses. The natural sulfate of strontium, SrSO4, it is important as a source of strontium and of certain of its compounds, e.g., strontium hydroxide, used in refining beet sugar, and strontium nitrate, used in red signal flares.

Pale blue to deep and splotchy blue, white, colorless, red-brown, orange. Luster glassy; hardness 3-3Ɖ; specific gravity 3.9-4.0; fracture uneven; cleavage like barite, perfect basal and prismatic and poor pinacoidal. Brittle; transparent to translucent; sometimes fluorescent.

Answer 4

Sounds to me like Barytes (Barite), Hardness is about right, it has one perfect cleavage (mica like layering), colourless/pale blue. Proof would be to test its specific gravity.
Another thought. If you can scrape a few fragments off into a flame and they turn green its almost certainly Barite.

Answer 5

Hmmm.... sounds like lazulite.

Answer 6

it may be quartz

Answer 7

maybe its quartz? ;p