Bismuth Crystals

[Hornbein]

Very unusual looking.

 

[davenn]

Very unusual looking.

Yeah, often found at mineral shows, they are lab grown, they dont normally grow like that in the ground
I have a couple of pieces like that here in my collection, if I remember, I will do a photo

 

[Hornbein]

Yeah, often found at mineral shows, they are lab grown, they dont normally grow like that in the ground
I have a couple of peices like that here in my collection, if I remember, I will do a photo

It has both metallic and crystalline forms. Does anything else or is this unique?

 

[davenn]

It has both metallic and crystalline forms. Does anything else or is this unique?

Metallic and crystalline are not mutually exclusive
Almost all metals have crystalline forms

Dave

 

[Hornbein]

Metallic and crystalline are not mutually exclusive
Almost all metals have crystalline forms

Dave

Aha. So it's the size of the crystals then. Do any metals aside from Bismuth so easily form large crystals like that.

 

[DaveE]

Aha. So it's the size of the crystals then. Do any metals aside from Bismuth so easily form large crystals like that.

Pure metals? "Like that", like what?
There is Galena (PbS), Pyrite (FeS₂), Stibnite (Sb₂S₃)
Plus more exotic metals: https://www.thoughtco.com/metal-crystals-photo-gallery-4054187

Brought to you by google search. I find it a very useful tool myself.

 

[Hornbein]

Huh, I thought metals had to be made of the elements, not compounds. I thought metals had to be flexible. The dictionaries say otherwise. They say the only requirements are that it be hard and conduct electricity and heat. There's no arguing with dictionaries, but in this case I believe they deviate from actual usage. If I were to use the word in this way I would be misunderstood.

I also learned that a "metalled road" is a road covered with crushed stone.

 

[DaveE]

Huh, I thought metals had to be made of the elements, not compounds. I thought metals had to be flexible. The dictionaries say otherwise. They say the only requirements are that it be hard and conduct electricity and heat. There's no arguing with dictionaries, but in this case I believe they deviate from actual usage. If I were to use the word in this way I would be misunderstood.

I also learned that a "metalled road" is a road covered with crushed stone.

I always thought that steel, bronze, and brass were metals. But that's the problem with vernacular language, it all depends on how you learned it. IDK.

But "flexible"? OK, whatever.

 

[Hornbein]

I always thought that steel, bronze, and brass were metals. But that's the problem with vernacular language, it all depends on how you learned it. IDK.

But "flexible"? OK, whatever.

Steel bronze and brass are alloys entirely composed of the elements (or so I believe anyway). No rule against mixing them.

 

[DaveE]

entirely composed of the elements

Perhaps you misspoke? Isn't that everything?
Also, I don't think the Carbon in Steel is a metal, but I'm bad at Chemistry and Carbon is weird.
Anyway my point is that common language fails in science when we start splitting hairs.

Anyway Gallium might be a good candidate. Like Bismuth it isn't toxic or very reactive, and has a low melting point.

 

[Hornbein]

Perhaps you misspoke? Isn't that everything?
Also, I don't think the Carbon in Steel is a metal, but I'm bad at Chemistry and Carbon is weird.
Anyway my point is that common language fails in science when we start splitting hairs.

Anyway Gallium might be a good candidate. Like Bismuth it isn't toxic or very reactive, and has a low melting point.

If I had written "composed entirely of an element" then I would have misspoken.

Carbon is an element so I say it's included. It's not a metal but that doesn't prevent it from being included in a metal.

I am puzzled by why the dictionary definition differs so much from common usage. Maybe chemists use that definition. But dictionaries make note of specialized usages.

 

[davenn]

Aha. So it's the size of the crystals then. Do any metals aside from Bismuth so easily form large crystals like that.

no, crystal size is irrelevent.
a crystal is a crystal regardless of it is 1mm or 1m in size
and it also doesnt matter if it is a metal or a non-metal element

 

[DaveE]

This has become a very strange thread. Perhaps I'm misunderstanding something.

 

[davenn]

It has both metallic and crystalline forms. Does anything else or is this unique?

This has become a very strange thread. Perhaps I'm misunderstanding something.

Hi Dave ... it's all because Hornbein didnt seem to realise that most metals have crystal forms
as I stated earlier. He appeared to think that the crystal habit of a metal was uncommon and that
a metallic substance ( pure element or mineral compound) couldnt be both a metal and a crystal.

The confusion comes with not realising that a crystal is just a form/habit of elements or minerals

Galena, PbS - Lead Sulphide - has a cubic crystal habit

But Fluorite - CaF2 - totally non-metallic, also has a Cubic crystal habit

Neither of those 2 are from my collection .... this next one is


Pyrite - FeS2 -Iron Sulphide - from my collection, also has a Cubic crystal habit

With only a quick look, Bismuth is the only native element that I found with a cubic crystal habit,
there may be other ones?

But there are many different crystal habits for all native elements and for minerals

A mineral, is just a combination of native elements as shown in the examples above

cheers
Dave

 

[Hornbein]

It appears one may grow large crystals of any of the metallic elements. This seldom occurs in nature and I suppose it isn't easy dealing with the necessary high temperatures. Iron crystals may sometimes be found in meteorites.

Sure enough, it's easy to make big gallium crystals.

I liked the theory that the celebrated 'Oumuamua asteroid is an intergalactic crystal of hydrogen. But such would not have survived solar radiation.

 

[Astronuc]

I always thought that steel, bronze, and brass were metals. But that's the problem with vernacular language, it all depends on how you learned it. IDK.

Steel, bronze and brass are metals and alloys. Alloys are just mixtures of metals. Depending on manufacturing method, there may be impurities of C, N, O, P and S, as well as others.

Pure metals are much more expensive. With pure metals, one would want to melt under vacuum to avoid pickup of N and O from the air, especially for reactive metals.

One can form interesting crystal structures by freezing metal vapors on a 'cold' mandrel/substrate (physical vapor deposition).

Colored surfaces due to different oxide layers is often performed with anodizing certain metals like Ti, Zr, Nb, or stainless steels. I've observed this in person.
Ref: https://en.wikipedia.org/wiki/Chemical_coloring_of_metals

From Google AI regarding Bi, "Bismuth crystallizes into a distinct rhombohedral structure (A7-type) belonging to the trigonal crystal system with the $R\bar{3}m$ space group. Its unique, stair-stepped "hopper" shape occurs because its outer edges grow faster than the inner faces as the metal rapidly solidifies and expands."

Bi has a relatively low melting point: 544.7 K (271.5 °C, 520.7 °F), which makes it easier to melt and form crystals.

 

[Astronuc]

Huh, I thought metals had to be made of the elements, not compounds. I thought metals had to be flexible. The dictionaries say otherwise. They say the only requirements are that it be hard and conduct electricity and heat. There's no arguing with dictionaries, but in this case I believe they deviate from actual usage. If I were to use the word in this way I would be misunderstood.

Element is the general term for each unique chemical species listed in the periodic table. Hydrogen, Helium, Lithium, Beryllium, Boron, Carbon, Nitrogen, Oxygen, Flourine, Neon, are the first 10 elements by atomic number (Z); the atomic number signifies the number of protons in the nucleus and the number of electrons surrounding the nucleus of atom, when it is electrically neutral. A loss of electrons yields a positive ion, while a gain of electrons yields a negative ion.

One can produce 'pure' metals, but that may mean 99.5%, 99.9%, 99.99%, . . . . The higher the level of purity, the more expensive.

Group 1 of the periodic table Li, Na, K, Rb, Cs, Fr are alkali metals. Note hydrogen (a diatomic gas) is not ordinarily metal unless it is cooled and compressed; one can make metallic hydrogen.

Group 2 in the periodic table, Be, Mg, Ca, Sr, Ba, Ra are alkali(ne) earth metals.

Groups 3-12 are transition metals.

Starting with Group 13, things get interesting regarding classification. Boron is considered a metalloid, while Al, Ga, In, and Tl are considered metals. Metalloids are elements with properties intermediate between metals and nonmetals.

Carbon is a nonmetal, while Si, Ge are considered metalloids (semiconductors) and Sn, Pb are metals.
This may help: https://periodictableguide.com/metalloids-located-on-the-periodic-table/
https://en.wikipedia.org/wiki/Metalloid

On a standard periodic table, metalloid elements form a diagonal, stair-step line separating the metals on the left from the nonmetals on the right. Depending on the classification system used, elements like Polonium (Po) and Astatine (At) are also sometimes classified as metalloids.

Most metals are not used in their pure form, but rather are alloyed; some elements are used in pure form, e.g., alkali metals like Li, Na and even Pb, for liquid metal cooled systems, but often Na is alloyed with K, and Pb is alloyed with Bi. Usually, the alloy is determined by the mixture with the lowest melting point. Of course, Au and Ag are used in their pure form as in bar form (bullion), but in more common usage such as jewelry, Au or Ag may be alloyed with aluminum, silicon, nickel, copper, cadmium, zinc, tin, . . . .