Talk:Lazurite

Image

"It (lazulite) is often confused with lazurite, lapis lazuli or azurite". I exchanged the images. image:Lazuryt,_Niemcy.jpg looks like lapislazuli to me, a mix of minerals. --Chris.urs-o (talk) 11:09, 2 February 2011 (UTC)

What is the chemical formula?

Ummm ... The different references have contradictory chemical formulas. I trust the one from Mindat.org. (Na, Ca)8 (Al6 Si6 O24) (S, SO4, Cl2). Please, a geologist sort this out.— Preceding unsigned comment added by 65.33.212.34 (talk • contribs) 09:34, 4 March 2011

One of the important things is that is contains the S3- ion to give it colour. That is not apparent in the formula, all we have is "s".— Preceding unsigned comment added by Graeme Bartlett (talk • contribs) 12:02, 4 March 2011

Can you cite an authoritative reference for that formula?

Heh. Theres also this formula: (Na,Ca)8 (Al6 Si6 O24)(S,SO4,Cl2). How can the same chemical have so many different formulas. —Preceding unsigned comment added by 65.33.212.34 (talk) 13:23, 4 March 2011 (UTC)

The formula in the article essentially follows the Hurbut and Klein reference, (the ref I used back in Jan. 06) the Handbook of Mineralogy ref only varies by adding hydroxide. Both of those are "authoritative refs". The Webmineral data site provides a shorter version and the Mindat website seems to be offline right now. Vsmith (talk) 13:58, 4 March 2011 (UTC)

Mindat accessed now and they agree with formula given - the diffs are mainly sleight variations in order and paren locations. Vsmith (talk) 14:11, 4 March 2011 (UTC)

There is a purist approach that one chemical formula and one crystal cell is one mineral, but reality is less strict. There are liquid IMA/CNMNC valid minerals (mercury), amorphous IMA/CNMNC valid minerals (allophane), and mineraloid IMA/CNMNC valid names (opal). Many minerals have a chemical formula as a range, some minerals don't have a complete description, yet. Lapis lazuli is the most expensive blue color of the antiquity, and Lazurite's chemical formula is one that is given as a range Na₆Ca₂Al₆Si₆O₂₄[(SO₄), S, Cl, (OH)]₂. --Chris.urs-o (talk) 12:59, 5 March 2011 (UTC)

Sorry, but you mix things up:

Reality is:

• each mineral has an IDEAL formula, that is COMPLETELY INVARIABLE; if an ideal formula is variable then we have more than a single mineral
• "one crystal cell is one mineral": this doesn't make sense at all

a crystal cell is a UNIT cell of a crystal; one crystal is a mineral, another one (e.g., a crystal of a virus; or any synthetic compound) is not - as simple as it is

• mercury IS NOT A MINERAL........... it is a mineralloid; also, mercury ALWAYS has the formula "Hg"
• allophane is not a mineral --- is is amorphous; however, it was known prior to IMA --> now it has the "grandfathered" status; it will soon be discredited
• Lapis lazuli IS NOT A MINERAL - it is actually a rock...

Thus, again, a suggestion: first - become a mineralogist, accept the MINERALOGY rules (IMA), THEN comment Eudialytos (talk) 22:26, 17 July 2023 (UTC)

and again you are showing off "knowledge" which in reality has no coverage.... in reality

sorry but you know what you are talking about Eudialytos (talk) 22:30, 17 July 2023 (UTC)

there is no such thing as "amorphous IMA/CNMNC valid minerals"

mineral species has a STATUS; some have more than a single status

allophane is a species NAMED before IMA --> IMA treats it as a GRANDFATHERED species

as a (most likely, actually) amorphous compound, allophane will be discredited

however,

first, some studies must be done to confirm what actually comprises allophane, or allophanes

This is how it works.

Eudialytos (talk) 22:28, 17 July 2023 (UTC)

This is, obviously, complex, because mineralogy has its own rights, as explained/set by the IMA (i.a.).

1.There are various types of formulas. Chemistry has its own types, and mineralogy has its own.

2. Each IMA-approved mineral species has an ideal formula (that may be, but does not necessarily has to be, a structural formula), and this formula is invariable.

3. Some people think that the parentheses with diadochy systems in minerals' formulas are mandatory. The reality is: sometimes yes (e.g., cation order case; stabilization of otherwise metastable structures), but usually not.

3. A lot of mineral species were first analyzed using old techniques; new techniques (e.g., micro-tts-diffraction, Pseudo-Gandolfi diffraction, neutron diffraction, PIXE/PIGE, micro-XANES, etc.) may sometimes show these species to:

(a) have a different structure (i.e., a better structural model is obtained) --> new formula

(b) turn out to be a mixture of more than a single species

a & b is known as redefinition

Eudialytos (talk) 22:37, 17 July 2023 (UTC)

Lots of changes to lazurite

Lazurite is not what was thought to be some years ago. New Russian data clearly shows it to be very rare, currently exclusively known from the Malo-Bystrinskoe deposit (Russia). ALL the lapis lazuli material is LACKING LAZURITE. The blue colourant of the Afghan rock is haüyne. Also, the correct formula is: Na7Ca(Al6Si6O24)(SO4)(S3)·H2O.Eudialytos (talk) 07:53, 27 June 2023 (UTC) Refs.:

https://www.mindat.org/min-2357.html

https://mineralogy-ima.org/Minlist.htm

Sapozhnikov, A.N., Chukanov, N.V., Shendrik, R.Yu., Vigasina, M.F., Tauson, V.L., Lipko, S.V., Belakovskiy, D.I., Levitskii, V.I., Suvorova, L.F., Ivanova, L.A. (2021): Lazurite: validation as a mineral species and new data. Zapiski RMO: 150: 92-102.