Answers.Body: <p>I would tend to say that any part produced for only one set would qualify, especially if said set is priced high. Looking at the inventory of <a href="http://www.bricklink.com/catalogItemInv.asp?S=10179-1">10179 Millenium Falcon UCS</a> for example, the following candidates come to mind:</p>
  
  <ul>
  <li><a href="http://www.bricklink.com/catalogItemIn.asp?P=47996&amp;colorID=86&amp;in=A">Light Bluish Gray Boat Mast Rigging Long 28 x 4</a></li>
  <li><a href="http://www.bricklink.com/catalogItem.asp?P=50990pb03">Dish 10 x 10 Inverted (Radar) with Radiating Spokes Pattern on Concave Side</a> although it's printed so I'm not sure you're willing to accept it. I would have mentionned minifigs as well, but only <a href="http://www.bricklink.com/catalogItem.asp?M=sw174">Obi-Wan Kenobi (Old, Light Flesh)</a> is exclusive to the set and its individual parts are used in other sets.</li>
  </ul>
  
  <p>Considering the <a href="http://www.bricklink.com/search.asp?itemID=68171">price the set goes for nowadays</a>, and the fact that most people who buy it will probably build it once and leave it so (that is, if they open the box at all), I think the grey boat mast rigging is a very good candidate. There are <a href="http://www.bricklink.com/search.asp?itemID=56261&amp;colorID=86">four people selling some on BrickLink</a> as of february 2013, but a glance at the prices asked comforts me in my reasoning. Even the printed radar dish is cheaper.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-02-12T02:30:13.287Z
Answers.Text: Agreed, I think the mast rigging is a good candidate. I think printed elements are acceptable but since both the radar and the mast rigging are both from the same set, I suppose it doesn't make any difference. Interesting point on the minifig - I would say that since it is made up of parts, then I would say the minifig as a whole doesn't count even though it is only used in that one set.
Answers.UserDisplayName: mcqwerty
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-02-11T08:42:54.437Z
Answers.LastActivityDate: 2013-02-11T19:05:03.910Z
Answers.LastEditDate: 2013-02-11T19:05:03.910Z
Answers.UserDisplayName: Joubarc
Answers.Body: <p>I'm not sure whether to consider these real Lego parts or not, but many of the old HO scale vehicles and greenery are incredibly rare. For example, the <a href="http://www.bricklink.com/search.asp?itemID=11699&amp;colorID=5" rel="noreferrer">Jaguar</a> is quite rare in any color, but especially in red and black.</p>
  
  <p><img src="https://i.sstatic.net/rUlxz.jpg" alt="enter image description here"></p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-02-12T02:43:40.073Z
Answers.Text: @jncranton I never thought of the old HO scale vehicles. I suppose we should also consider the [Pull-Along Duck from 1935](http://www.bricklink.com/catalogItem.asp?G=pullduck), there can't be many of those still around.
Answers.UserDisplayName: mcqwerty
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-02-12T11:31:08.367Z
Answers.Text: +1 for this - although I feel the question is a bit vague in this respect in that @mcqwerty didn't actually specify what "element" meant ;)
Answers.UserDisplayName: Zhaph - Ben Duguid
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Answers.CreationDate: 2013-02-12T01:22:32.593Z
Answers.LastActivityDate: 2013-02-12T01:22:32.593Z
Answers.UserDisplayName: jncraton
Answers.Body: <p><strong>712pb01 Plate, Round Curved 4 x 8 Left with Red Line on Curved Edge Pattern</strong></p>
  
  <p>To be honest, I don't know if this is especially rare. I do know, however, that to find the rarest part we'll need to factor in:</p>
  
  <p><strong>1. Parts that appear in small numbers in very few sets</strong></p>
  
  <p>For example:</p>
  
  <ul>
  <li>"White Minifig, Headgear Hair Female Pigtails" piece only appeared <a href="http://www.bricklink.com/catalogItemIn.asp?P=x103&amp;in=S">in a few sets</a>.</li>
  <li>The parts unique to the 10179 Millennium Falcon UCS.</li>
  </ul>
  
  <p>Often, rare parts have an unusual design or colour.</p>
  
  <p><strong>2. Of those, sets that had a limited production run</strong></p>
  
  <p>Sets with a limited run might include:</p>
  
  <ul>
  <li>Promotional sets (although these rarely have unique parts)</li>
  <li>Sets that are limited to a single locality</li>
  </ul>
  
  <p>The Millennium Falcon might be a candidate here.</p>
  
  <p><strong>3. Of those, parts that are unlikely to have survived the ravages of time</strong></p>
  
  <p>This might include:</p>
  
  <ul>
  <li>Old sets - anything from the 1950s, for example</li>
  <li>Sets designed for community play, e.g. Educational establishments</li>
  </ul>
  
  <p>All things considered, I imagine that the rarest piece of proper LEGO is from one of the oldest sets: which is why I suggest something like, "<a href="http://www.bricklink.com/catalogItem.asp?P=712pb01">712pb01 Plate, Round Curved 4 x 8 Left with Red Line on Curved Edge Pattern</a>" that appeared in a single set in 1958.</p>
  
  <p>Alternatively, (if you care to count them as part of the system) many of the parts from the 1940s Automatic Binding Bricks era will be quite rare by now.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-02-13T08:21:51.980Z
Answers.Text: How could I forget about the white minifig female hair... (although in all fairness I've seen some sold at auctions a few years ago, and these were even provided by LEGO itself)
Answers.UserDisplayName: Joubarc
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-02-12T11:55:56.667Z
Answers.LastActivityDate: 2013-02-12T11:55:56.667Z
Answers.UserDisplayName: Kramii
Answers.Body: <p>I was just reading about the 8485 Technic Control Center II, where you can make a dinosaur, helicopter, or hovercraft controlled by a big panel, and which I have on hand. According to a reviewer (<a href="http://www.eurobricks.com/forum/index.php?showtopic=75864">http://www.eurobricks.com/forum/index.php?showtopic=75864</a>) there are a few rare pieces that were included with this set, which retailed for $219 in 1995. The price of the set and quickly-outdated electronics probably could imply that the set is relatively rare. Some of the parts are pictured here - <a href="http://www.flickr.com/photos/mostlytechnic/8158411568/">http://www.flickr.com/photos/mostlytechnic/8158411568/</a>
  Red wing plates (x2 Left, x2 Right) that were used in the helicopter build, and one other set.
  Little white coils for bundling wires together, only used in an earlier Multi Control set and educational sets (probably quickly lost).
  And a black steering yoke used in the dinosaur build - only ever included in this set. It was released in white in a 1980s car set.</p>
  
  <p>This might be one of the rarest individual parts that's not from a promotional or movie-themed set.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2014-03-04T20:10:12.253Z
Answers.Text: None of these seem to fetch too high a price - admittedly, that's not necessarily an indication of their rarity, but since the demand isn't particularly high it's still possible to get some relatively easily. Good find, though - and welcome to bricks.se!
Answers.UserDisplayName: Joubarc
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2014-03-04T19:50:47.570Z
Answers.LastActivityDate: 2014-03-04T19:50:47.570Z
Answers.UserDisplayName: Crissy
Answers.Body: <p>It's impossible to provide an accurate answer without accurate information to base it off of.  Without knowing production quantities on every set, it is impossible to know if there's a part that only comes one per copy of a set that sold 10 million units, or if there's another part that only comes ten copies of a set that sold 10,000 units.  Age of sets can also affect the answer because parts that have not been made in decades will exist in much smaller numbers now than when they were brand-new, due to all the various ways that a LEGO part could be destroyed over the years.  Some sets have been recalled and changed, which may have allowed a small number of a rare element to make it out into the wild, after which the supply was cut off.  And some elements have been retired almost immediately after they were first put into production.  Assuming stuff like SDCC minifigs are excluded (not meant to be sold), I have to put my vote on 8-spoked wheel #51377.  In 2005, they first introduced this wheel in metallic-silver for a Designer set and a Tiny Turbos set.  In 2006, they produced it in pearl-gold for the first Batmobile and the Catwoman/Dragster set.  Before those two Batman sets went out of production, they had introduced the reversible wheel #55981 with six spokes on one side and bolts on the other.  In the two Batman sets, they replaced the 8-spoke wheel with the new reversible one, which means they made the 8-spoke wheel in pearl-gold for only a few months before the mold was permanently retired.  I bought one copy of each Batman set at release, and a second copy soon after, and only got the 8-spoke wheel in the first copies I bought.  And that's too bad, because it's a really cool looking wheel.</p>
  
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Answers.CreationDate: 2018-02-03T15:39:11.577Z
Answers.LastActivityDate: 2018-02-03T15:39:11.577Z
Answers.UserDisplayName: Purple Dave
Answers.Body: <p>How about a surprisingly rare part: the Lime Green 1x1 plate. Only produced in one set in 2005.</p>
  
  <p>Edit: Re-issued in 2014,so for 9 years, it was rare.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-01-22T08:14:39.480Z
Answers.Text: Oh? Bricklink says it was in [three sets](http://www.bricklink.com/catalogItem.asp?P=3024).
  
  granted, one of those sets is a monthly mini model build.
  
  OTOH, Bricklink says 6 different colors of 1x1 plate came in only one set each. Of those, the Maersk blue only had two in a set from 1980.
Answers.UserDisplayName: gev
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-01-22T14:57:11.610Z
Answers.Text: I didn't realize they re-released it! Brickset still lists it as only coming in the one set from 10 years ago, and when I went looking to buy some last year, they were $1+ each on Bricklink.
  
  Anyway, I think a much more interesting answer to this question than a rare one-off piece for a licensed set is a common color and common part that in combination are rare.
Answers.UserDisplayName: oddTodd
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-01-23T08:15:54.490Z
Answers.Text: At this point, I'd be interested to see what mcqwerty has to say, what with all this new activity and STILL without a chosen answer.
Answers.UserDisplayName: gev
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-05-18T02:29:07.413Z
Answers.Text: @gev I am here, watching and enjoying the conversation. I'm not sure there is a 'correct' answer since it depends on even more factors than listed in my original question.
Answers.UserDisplayName: mcqwerty
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-01-22T03:58:23.377Z
Answers.LastActivityDate: 2015-01-23T16:06:06.790Z
Answers.LastEditDate: 2015-01-23T16:06:06.790Z
Answers.UserDisplayName: oddTodd
Answers.Body: <p>Perhaps the <a href="http://www.bricklink.com/search.asp?itemID=1057&amp;colorID=64" rel="nofollow">Chrome Green Rock 1 x 1 Crystal 5 Point</a>?</p>
  
  <p>It is the only chrome green part.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-01-21T08:24:37.877Z
Answers.LastActivityDate: 2015-01-21T08:24:37.877Z
Answers.UserDisplayName: gev
Answers.Body: <p>Based on the conversation in this <a href="https://bricks.stackexchange.com/questions/5953/does-someone-know-where-i-can-find-this-lego-brick">thread</a>, the 2x4 brick in trans-neon-green is also quite rare. Last selling price on Bricklink was from Oct 2014 and was set to $75.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2018-06-12T08:44:47.390Z
Answers.Text: As that part was never in any set (the linked thread says so), it probably is a prototype element or something and thus fails some of the OP's criteria.
Answers.UserDisplayName: Henrik supports the community
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Answers.CreationDate: 2015-01-20T19:35:17.653Z
Answers.LastActivityDate: 2015-01-20T19:35:17.653Z
Answers.LastEditDate: 2017-04-13T12:47:56.390Z
Answers.UserDisplayName: Phil B.
Answers.Body: <p>Antannae piece from the 70s. The ones nowadays are almost all broken, so these are rare. Also Chrome Gold 2x2</p>
  
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Answers.CreationDate: 2020-04-01T20:32:01.973Z
Answers.LastActivityDate: 2020-04-01T20:32:01.973Z
Answers.UserDisplayName: user15030
Body: <p>What is the rarest LEGO element according to the following criteria:</p>
  
  <ul>
  <li>Genuine LEGO elements, not those available through third party vendors or otherwise modified elements. (So nothing from <a href="http://www.brickarms.com/">Brickarms.com</a>, <a href="http://www.bricklink.com/store.asp?p=ChromeBricks">ChromeBricks.com</a>, etc.)</li>
  <li>Not prototype elements such as the <a href="http://lego.wikia.com/wiki/File%3aGhost_red.jpg">Red Ghost</a>, <a href="http://www.bricklink.com/search.asp?itemID=2104&amp;colorID=3">Yellow</a> or <a href="http://www.bricklink.com/search.asp?itemID=2104&amp;colorID=5">Red Train Rails</a>, etc.</li>
  <li>The same element of a different colour counts as a different element,
  (so the rarest colour/element combination)</li>
  <li>No special production elements such as the <a href="http://www.brickenvy.com/Shop/p-482-14k-Solid-Gold-LEGO-Employee-Brick-2x4-Brick-in-Display-Box.html">14k Solid Gold LEGO Employee Brick 2x4 Brick in Display Box</a> or <a href="http://rads.stackoverflow.com/amzn/click/B0015PJNJ8">Gold C-3P0</a>.</li>
  <li>No elements that were only part of sets produced not to be sold, such as the unique <a href="http://www.bricklink.com/catalogItem.asp?P=4000001stk01">Sticker for Set 4000001</a> which is part of set <a href="http://www.brickset.com/detail/?Set=4000001-1">LEGO Inside Tour (LIT) Exclusive 2011 Edition - Moulding Machines</a> or the <a href="http://www.bricklink.com/catalogItemIn.asp?P=6082&amp;colorID=6&amp;in=A">Green BURP</a> from the <a href="http://www.brickset.com/detail/?Set=4999-1">Wind Turbine - Vestas promotional set</a>.</li>
  </ul>
  
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2013-02-11T08:26:05.460Z
Comments.Text: Agood example of "part of sets produced not to be sold" would be the [green BURP](http://www.bricklink.com/catalogItemIn.asp?P=6082&colorID=6&in=A), as it's only been used in that one set which was only given to Vestas employees (not that some didn't make it to the market, of course, and I've seen the green BURP in bulk actions in some rare instances). Barring that, I believe that at some point LEGOland parks did have access to more elements in alternate colours, but that probably doesn't count either since these weren't supposed to be released to the public.
Comments.UserDisplayName: Joubarc
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2013-02-12T02:51:08.693Z
Comments.Text: @Joubarc Nice example, I have updated the question to include it. (Now I want to go and buy some Green BURPs!)
Comments.UserDisplayName: mcqwerty
Tags: <piece-information>
Title: What is the rarest LEGO production element (colour/shape combination)?
UserDisplayName: mcqwerty
ThreadText: # What is the rarest LEGO production element (colour/shape combination)?
  
  (Asked by: username_0 on 2013-02-11)
  
  What is the rarest LEGO element according to the following criteria:
  
  * Genuine LEGO elements, not those available through third party vendors or otherwise modified elements. (So nothing from [Brickarms.com](http://www.brickarms.com/), [ChromeBricks.com](http://www.bricklink.com/store.asp?p=ChromeBricks), etc.)
  * Not prototype elements such as the [Red Ghost](http://lego.wikia.com/wiki/File%3aGhost_red.jpg), [Yellow](http://www.bricklink.com/search.asp?itemID=2104&colorID=3) or [Red Train Rails](http://www.bricklink.com/search.asp?itemID=2104&colorID=5), etc.
  * The same element of a different colour counts as a different element,
    (so the rarest colour/element combination)
  * No special production elements such as the [14k Solid Gold LEGO Employee Brick 2x4 Brick in Display Box](http://www.brickenvy.com/Shop/p-482-14k-Solid-Gold-LEGO-Employee-Brick-2x4-Brick-in-Display-Box.html) or [Gold C-3P0](http://rads.stackoverflow.com/amzn/click/B0015PJNJ8).
  * No elements that were only part of sets produced not to be sold, such as the unique [Sticker for Set 4000001](http://www.bricklink.com/catalogItem.asp?P=4000001stk01) which is part of set [LEGO Inside Tour (LIT) Exclusive 2011 Edition - Moulding Machines](http://www.brickset.com/detail/?Set=4000001-1) or the [Green BURP](http://www.bricklink.com/catalogItemIn.asp?P=6082&colorID=6&in=A) from the [Wind Turbine - Vestas promotional set](http://www.brickset.com/detail/?Set=4999-1).
  
  **Tags:** piece-information
  > **Comments:**
  > **username_1**: Agood example of "part of sets produced not to be sold" would be the [green BURP](http://www.bricklink.com/catalogItemIn.asp?P=6082&colorID=6&in=A), as it's only been used in that one set which was only given to Vestas employees (not that some didn't make it to the market, of course, and I've seen the green BURP in bulk actions in some rare instances). Barring that, I believe that at some point LEGOland parks did have access to more elements in alternate colours, but that probably doesn't count either since these weren't supposed to be released to the public.  
  > **username_0**: @Joubarc Nice example, I have updated the question to include it. (Now I want to go and buy some Green BURPs!)  
  
  ---
  
  ## 9 answers
  
  ### Answer by username_1 on 2013-02-11. Score: 13
  
  I would tend to say that any part produced for only one set would qualify, especially if said set is priced high. Looking at the inventory of [10179 Millenium Falcon UCS](http://www.bricklink.com/catalogItemInv.asp?S=10179-1) for example, the following candidates come to mind:
  
  * [Light Bluish Gray Boat Mast Rigging Long 28 x 4](http://www.bricklink.com/catalogItemIn.asp?P=47996&colorID=86&in=A)
  * [Dish 10 x 10 Inverted (Radar) with Radiating Spokes Pattern on Concave Side](http://www.bricklink.com/catalogItem.asp?P=50990pb03) although it's printed so I'm not sure you're willing to accept it. I would have mentionned minifigs as well, but only [Obi-Wan Kenobi (Old, Light Flesh)](http://www.bricklink.com/catalogItem.asp?M=sw174) is exclusive to the set and its individual parts are used in other sets.
  
  Considering the [price the set goes for nowadays](http://www.bricklink.com/search.asp?itemID=68171), and the fact that most people who buy it will probably build it once and leave it so (that is, if they open the box at all), I think the grey boat mast rigging is a very good candidate. There are [four people selling some on BrickLink](http://www.bricklink.com/search.asp?itemID=56261&colorID=86) as of february 2013, but a glance at the prices asked comforts me in my reasoning. Even the printed radar dish is cheaper.
  
  > **Comments:**
  > **username_0**: Agreed, I think the mast rigging is a good candidate. I think printed elements are acceptable but since both the radar and the mast rigging are both from the same set, I suppose it doesn't make any difference. Interesting point on the minifig - I would say that since it is made up of parts, then I would say the minifig as a whole doesn't count even though it is only used in that one set.  
  
  ---
  
  ### Answer by username_2 on 2013-02-12. Score: 10
  
  I'm not sure whether to consider these real Lego parts or not, but many of the old HO scale vehicles and greenery are incredibly rare. For example, the [Jaguar](http://www.bricklink.com/search.asp?itemID=11699&colorID=5) is quite rare in any color, but especially in red and black.
  
  ![enter image description here](https://i.sstatic.net/rUlxz.jpg)
  
  > **Comments:**
  > **username_0**: @jncranton I never thought of the old HO scale vehicles. I suppose we should also consider the [Pull-Along Duck from 1935](http://www.bricklink.com/catalogItem.asp?G=pullduck), there can't be many of those still around.  
  > **username_3**: +1 for this - although I feel the question is a bit vague in this respect in that @mcqwerty didn't actually specify what "element" meant ;)  
  
  ---
  
  ### Answer by username_4 on 2013-02-12. Score: 8
  
  **712pb01 Plate, Round Curved 4 x 8 Left with Red Line on Curved Edge Pattern**
  
  To be honest, I don't know if this is especially rare. I do know, however, that to find the rarest part we'll need to factor in:
  
  **1. Parts that appear in small numbers in very few sets**
  
  For example:
  
  * "White Minifig, Headgear Hair Female Pigtails" piece only appeared [in a few sets](http://www.bricklink.com/catalogItemIn.asp?P=x103&in=S).
  * The parts unique to the 10179 Millennium Falcon UCS.
  
  Often, rare parts have an unusual design or colour.
  
  **2. Of those, sets that had a limited production run**
  
  Sets with a limited run might include:
  
  * Promotional sets (although these rarely have unique parts)
  * Sets that are limited to a single locality
  
  The Millennium Falcon might be a candidate here.
  
  **3. Of those, parts that are unlikely to have survived the ravages of time**
  
  This might include:
  
  * Old sets - anything from the 1950s, for example
  * Sets designed for community play, e.g. Educational establishments
  
  All things considered, I imagine that the rarest piece of proper LEGO is from one of the oldest sets: which is why I suggest something like, "[712pb01 Plate, Round Curved 4 x 8 Left with Red Line on Curved Edge Pattern](http://www.bricklink.com/catalogItem.asp?P=712pb01)" that appeared in a single set in 1958.
  
  Alternatively, (if you care to count them as part of the system) many of the parts from the 1940s Automatic Binding Bricks era will be quite rare by now.
  
  > **Comments:**
  > **username_1**: How could I forget about the white minifig female hair... (although in all fairness I've seen some sold at auctions a few years ago, and these were even provided by LEGO itself)  
  
  ---
  
  ### Answer by username_5 on 2014-03-04. Score: 5
  
  I was just reading about the 8485 Technic Control Center II, where you can make a dinosaur, helicopter, or hovercraft controlled by a big panel, and which I have on hand. According to a reviewer (<http://www.eurobricks.com/forum/index.php?showtopic=75864>) there are a few rare pieces that were included with this set, which retailed for $219 in 1995. The price of the set and quickly-outdated electronics probably could imply that the set is relatively rare. Some of the parts are pictured here - <http://www.flickr.com/photos/mostlytechnic/8158411568/>
  Red wing plates (x2 Left, x2 Right) that were used in the helicopter build, and one other set.
  Little white coils for bundling wires together, only used in an earlier Multi Control set and educational sets (probably quickly lost).
  And a black steering yoke used in the dinosaur build - only ever included in this set. It was released in white in a 1980s car set.
  
  This might be one of the rarest individual parts that's not from a promotional or movie-themed set.
  
  > **Comments:**
  > **username_1**: None of these seem to fetch too high a price - admittedly, that's not necessarily an indication of their rarity, but since the demand isn't particularly high it's still possible to get some relatively easily. Good find, though - and welcome to bricks.se!  
  
  ---
  
  ### Answer by username_6 on 2018-02-03. Score: 1
  
  It's impossible to provide an accurate answer without accurate information to base it off of. Without knowing production quantities on every set, it is impossible to know if there's a part that only comes one per copy of a set that sold 10 million units, or if there's another part that only comes ten copies of a set that sold 10,000 units. Age of sets can also affect the answer because parts that have not been made in decades will exist in much smaller numbers now than when they were brand-new, due to all the various ways that a LEGO part could be destroyed over the years. Some sets have been recalled and changed, which may have allowed a small number of a rare element to make it out into the wild, after which the supply was cut off. And some elements have been retired almost immediately after they were first put into production. Assuming stuff like SDCC minifigs are excluded (not meant to be sold), I have to put my vote on 8-spoked wheel #51377. In 2005, they first introduced this wheel in metallic-silver for a Designer set and a Tiny Turbos set. In 2006, they produced it in pearl-gold for the first Batmobile and the Catwoman/Dragster set. Before those two Batman sets went out of production, they had introduced the reversible wheel #55981 with six spokes on one side and bolts on the other. In the two Batman sets, they replaced the 8-spoke wheel with the new reversible one, which means they made the 8-spoke wheel in pearl-gold for only a few months before the mold was permanently retired. I bought one copy of each Batman set at release, and a second copy soon after, and only got the 8-spoke wheel in the first copies I bought. And that's too bad, because it's a really cool looking wheel.
  
  
  ---
  
  ### Answer by username_7 on 2015-01-22. Score: 1
  
  How about a surprisingly rare part: the Lime Green 1x1 plate. Only produced in one set in 2005.
  
  Edit: Re-issued in 2014,so for 9 years, it was rare.
  
  > **Comments:**
  > **username_8**: Oh? Bricklink says it was in [three sets](http://www.bricklink.com/catalogItem.asp?P=3024).  granted, one of those sets is a monthly mini model build.  OTOH, Bricklink says 6 different colors of 1x1 plate came in only one set each. Of those, the Maersk blue only had two in a set from 1980.  
  > **username_7**: I didn't realize they re-released it! Brickset still lists it as only coming in the one set from 10 years ago, and when I went looking to buy some last year, they were $1+ each on Bricklink.  Anyway, I think a much more interesting answer to this question than a rare one-off piece for a licensed set is a common color and common part that in combination are rare.  
  > **username_8**: At this point, I'd be interested to see what mcqwerty has to say, what with all this new activity and STILL without a chosen answer.  
  > **username_0**: @gev I am here, watching and enjoying the conversation. I'm not sure there is a 'correct' answer since it depends on even more factors than listed in my original question.  
  
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  ### Answer by username_8 on 2015-01-21. Score: 1
  
  Perhaps the [Chrome Green Rock 1 x 1 Crystal 5 Point](http://www.bricklink.com/search.asp?itemID=1057&colorID=64)?
  
  It is the only chrome green part.
  
  
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  ### Answer by username_9 on 2015-01-20. Score: 1
  
  Based on the conversation in this [thread](https://bricks.stackexchange.com/questions/5953/does-someone-know-where-i-can-find-this-lego-brick), the 2x4 brick in trans-neon-green is also quite rare. Last selling price on Bricklink was from Oct 2014 and was set to $75.
  
  > **Comments:**
  > **username_10**: As that part was never in any set (the linked thread says so), it probably is a prototype element or something and thus fails some of the OP's criteria.  
  
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  ### Answer by username_11 on 2020-04-01. Score: 0
  
  Antannae piece from the 70s. The ones nowadays are almost all broken, so these are rare. Also Chrome Gold 2x2
  
  
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