# Help me find a polyhedron! **URL:** \ **Category:** Factual Questions\ **Created:** [February 14, 2007, 4:06pm UTC](https://boards.straightdope.com/t/help-me-find-a-polyhedron/392208 "2007-02-14T16:06:01Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![Dijon\_Warlock](https://avatars.discourse-cdn.com/v4/letter/d/a9a28c/32.png) [@Dijon\_Warlock](https://boards.straightdope.com/u/Dijon_Warlock)\ **Post date:** [February 14, 2007, 4:06pm UTC](https://boards.straightdope.com/t/help-me-find-a-polyhedron/392208/1 "2007-02-14T16:06:01Z")
I’m looking for a model of a particular beast known as a “[rhombic dodecahedron](http://mathworld.wolfram.com/RhombicDodecahedron.html).” I want a solid one, about chicken-egg to tennis-ball size. Ideally (most likely way beyond my financial means), it would be quartz crystal. Less ideally (but more affordable) would be glass–like an optical prism. Even less ideally than that, but most likely realistically within my affordability range, would be plastic or something. Unacceptable is a template to make my own paper version, or even toys that build polyhedra by constructing the edges and asking you to imagine the rest. Any ideas? ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [February 14, 2007, 4:24pm UTC](https://boards.straightdope.com/t/help-me-find-a-polyhedron/392208/2 "2007-02-14T16:24:10Z")
A quick search shows that there are many sites that will give you those templates, which is the fastest and easiest way to meet your requirement. You say that you don’t want to do that – but when I was at MIT there was an advertisement up on the bulletin boarde by a guy whose business was making just such heavy-paper-scored-with-exacto-knife-and-glued/taped-together models. he adertised with a model of just such a solid on his bullertin-boardf ad. So f you don’t want to do it yourself, you can _hire_ someone to do it. You don’t even need to search for such a guy – just give a model-making friend the url of a template site and pay him/her. [http://search.yahoo.com/search?p=polyhedra+models&fr=yfp-t-501&toggle=1&cop=mss&ei=UTF-8](http://search.yahoo.com/search?p=polyhedra+models&fr=yfp-t-501&toggle=1&cop=mss&ei=UTF-8) > **[Polyhedron model](https://en.wikipedia.org/wiki/Polyhedron_model)** > > A polyhedron model is a physical construction of a polyhedron, constructed from cardboard, plastic board, wood board or other panel material, or, less commonly, solid material. > Since there are 75 uniform polyhedra, including the five regular convex polyhedra, five polyhedral compounds, four Kepler-Poinsot polyhedra, and thirteen Archimedean solids, constructing or collecting polyhedron models has become a common mathematical recreation. Polyhedron models are found in mathematics classrooms much... If you’re looking for something a little more solid, try these folks: [http://www.ics.uci.edu/~eppstein/junkyard/polymodel.html](http://www.ics.uci.edu/~eppstein/junkyard/polymodel.html) > **[Learning Resources](https://www.worldwideshoppingmall.com/learning-resources)** > > A wide range of Educational products are available from Learning Resources.Ranging from games, to more traditional educational toys. They offer a wide selection of products themed around making learning fun for children of all ages. They also offer a... ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [February 14, 2007, 4:29pm UTC](https://boards.straightdope.com/t/help-me-find-a-polyhedron/392208/3 "2007-02-14T16:29:26Z")
[This page on dice](http://www.dicecollector.com/diceinfo_how_many_shapes.html) lists several manufacturers of rhombic dodecahedrons. I picked up a 2" regular decahedron made of rose quartz at a rock show, but have never found a rhombic at same. ---
**Author:** ![xnylder](https://avatars.discourse-cdn.com/v4/letter/x/bbce88/32.png) [@xnylder](https://boards.straightdope.com/u/xnylder)\ **Post date:** [February 14, 2007, 5:56pm UTC](https://boards.straightdope.com/t/help-me-find-a-polyhedron/392208/4 "2007-02-14T17:56:05Z")
[QUOTE=Squink] [This page on dice](http://www.dicecollector.com/diceinfo_how_many_shapes.html) lists several manufacturers of rhombic dodecahedrons. I picked up a 2" regular decahedron made of rose quartz at a rock show, but have never found a rhombic at same. [/QUOTE] Thanks to **Squink** ’s post, I now know what you can ask for: a d30 (pronounced dee-thirty). Asking for this at the right gaming store or dice site (like the ones in the link) can get you a nice one. Assuming, of course, you don’t mind numbers on each face… (And yes, I own one. It is about the size of a large marble. And no, I haven’t managed to pass it off as a d20 in game…yet 😃 ) ---
**Author:** ![MikeS](https://avatars.discourse-cdn.com/v4/letter/m/919ad9/32.png) [@MikeS](https://boards.straightdope.com/u/MikeS)\ **Post date:** [February 14, 2007, 8:46pm UTC](https://boards.straightdope.com/t/help-me-find-a-polyhedron/392208/5 "2007-02-14T20:46:12Z")
What you want is a [garnet crystal](http://www.nps.gov/archive/brca/Geodetect/Photo%20book/RM%20pix/pages/Garnet-crystal-&-quarter-fo_jpg.htm). They occur naturally in this shape. Price may be an issue, though. There’s also some nice dodecahedral garnets pictured in [this eBay auction](http://cgi.ebay.com/Gem-Spessartite-GARNET-SMOKY-QUARTZ-crystal-CHINA_W0QQitemZ130075572766QQcmdZViewItem). ---
**Author:** ![The\_Controvert](https://avatars.discourse-cdn.com/v4/letter/t/dec6dc/32.png) [@The\_Controvert](https://boards.straightdope.com/u/The_Controvert)\ **Post date:** [February 14, 2007, 8:59pm UTC](https://boards.straightdope.com/t/help-me-find-a-polyhedron/392208/6 "2007-02-14T20:59:10Z")
[QUOTE=xnylder] Thanks to **Squink** ’s post, I now know what you can ask for: a d30 (pronounced dee-thirty). [/QUOTE] I’m not sure a Rhombic Dodecahedron has 30 sides. I think it has 12. According to this page, UNI\*SUN makes them: > **[DiceCollector.com -](http://www.dicecollector.com/diceinfo_how_many_shapes.html)** ---
**Author:** ![xnylder](https://avatars.discourse-cdn.com/v4/letter/x/bbce88/32.png) [@xnylder](https://boards.straightdope.com/u/xnylder)\ **Post date:** [February 14, 2007, 9:57pm UTC](https://boards.straightdope.com/t/help-me-find-a-polyhedron/392208/7 "2007-02-14T21:57:00Z")
[QUOTE=The Controvert] I’m not sure a Rhombic Dodecahedron has 30 sides. I think it has 12. According to this page, UNI\*SUN makes them: > **[DiceCollector.com -](http://www.dicecollector.com/diceinfo_how_many_shapes.html)** [/QUOTE] :smack: Sorry, I read the table wrong. And that shape isn’t a regular d12 anyway. \ ---
**Author:** ![Dijon\_Warlock](https://avatars.discourse-cdn.com/v4/letter/d/a9a28c/32.png) [@Dijon\_Warlock](https://boards.straightdope.com/u/Dijon_Warlock)\ **Post date:** [February 15, 2007, 8:40pm UTC](https://boards.straightdope.com/t/help-me-find-a-polyhedron/392208/8 "2007-02-15T20:40:50Z")
[QUOTE=xnylder] :smack: Sorry, I read the table wrong. And that shape isn’t a regular d12 anyway. \ [/QUOTE] 'Sokay…I appreciate you trying. Yeah, what I’m looking for has 12 faces (hence the “dodecahedron” part), but the faces must be congruent rhombii…rhombuses…rhomboids… I want it at (ideally) 2-3 inches through its longest axis, and transparent…but I’ll settle for what I can get and afford (Plastic/acrylic wouldn’t be horrible). I’ve been through the links that people have posted here, but the only thing I’m seeing is on the [www.dicecollector.com](http://www.dicecollector.com) site (thanks, **Squink** & **The Controvert** ). At least they have the RhomDo (as I like to call it, now…) dice. Still, not quite what I’m searching for, but in the absence of better alternatives, it may have to do. The garnets look to be the right shape, but are really too small for what I was shooting for. Still, they are natural manifestations of the form, so that’s something to keep in mind. Thank you for that. Another question that has come up in this quest has been “What minerals/elements naturally form this shape if not interferred with?” I want my goal to be solid and transparent; but having color wouldn’t be a horrible thing, so long as it’s not opaque/translucent…unless that’s all I can get. I’m also wondering if quartz can be faceted to this shape since it seems to have hexagonal geometry… ---
**Author:** ![Myron\_Van\_Horowitzski](https://avatars.discourse-cdn.com/v4/letter/m/9de053/32.png) [@Myron\_Van\_Horowitzski](https://boards.straightdope.com/u/Myron_Van_Horowitzski)\ **Post date:** [February 16, 2007, 2:22am UTC](https://boards.straightdope.com/t/help-me-find-a-polyhedron/392208/9 "2007-02-16T02:22:05Z")
[QUOTE=xnylder] Thanks to **Squink** ’s post, I now know what you can ask for: a d30 (pronounced dee-thirty). Asking for this at the right gaming store or dice site (like the ones in the link) can get you a nice one. Assuming, of course, you don’t mind numbers on each face… (And yes, I own one. It is about the size of a large marble. And no, I haven’t managed to pass it off as a d20 in game…yet 😃 ) [/QUOTE] Here is a [d30](http://www.thinkgeek.com/geektoys/cubegoodies/8ca5/). Or the same shape as one, anyway. Looks like lots of fun. ---
**Author:** ![Sapo](https://avatars.discourse-cdn.com/v4/letter/s/ec9cab/32.png) [@Sapo](https://boards.straightdope.com/u/Sapo)\ **Post date:** [February 16, 2007, 2:43am UTC](https://boards.straightdope.com/t/help-me-find-a-polyhedron/392208/10 "2007-02-16T02:43:45Z")
How about making your own cardboard mold and pouring it in clear acrylic?. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [February 16, 2007, 2:56am UTC](https://boards.straightdope.com/t/help-me-find-a-polyhedron/392208/11 "2007-02-16T02:56:49Z")
Googling on (“polyhedra models” rhombic) returns, among others, this: [http://www.y-math.nl/rombics.htm](http://www.y-math.nl/rombics.htm) Which includes solid rhombic dodecahedrons. Email the proprietor for prices. … [These people](http://www.peda.com/models/) sell a nice set of cast metal polyhedra, but I don’t see rhombic dodecahedrons on their list.