The BBC website has some concept art showing the red gemstones that the Doctor has at the beginning of the episode:
http://www.bbc.co.uk/programmes/p04m9xwd/p04m9wp6


After a quick Amazon search, I managed to find some red acrylic gemstones that look very similar to the ones from the Christmas special.

UK link:
https://www.amazon.co.uk/gp/aw/d/B00BVW1AJQ/ref=mp_s_a_1_6?ie=UTF8&qid=1482848464&sr=8-6&pi=AC_SX236_SY340_QL65&keywords=red+acrylic+rocks&dpPl=1&dpID=31P-8LnaJ3L&ref=plSrch

US link:
https://www.amazon.com/gp/aw/d/B00LHKVSUI/ref=mp_s_a_1_1?ie=UTF8&qid=1482848674&sr=8-1&pi=SY200_QL40&keywords=red+acrylic+rocks&dpPl=1&dpID=41pI6cqYZ6L&ref=plSrch

And, according to the product descriptions, the gemstones are 25mm in length, which matches the measurements given on the concept art.

Kind regards, The14thDr

Ones? I thought only one was seen?

just had a quick look at the episode & it looks like no. 05 that they used.



I rather like the "01" or "07" myself

Chris.

"Well, it's more than a gemstone - it's also like a kind of onboard computer. ... Formed in the heart of a red hole and stabilised in pure dwarf star crystal! ... There's only four of them left in the universe. The Apocalypse Monks of the Andorax called this one the Hazandra - the Ghost of Love and Wishes."

This small thing had so little screen time I can barely remember its shape, but I think No. 05 is about right. (Thanks for finding that concept art and posting it, 14th!) And besides the Amazon links, I think I've seen these shapes in craft stores when wandering around with the wife while she's looking for baubles for some of her projects. So that's another possible source for one of these. (And like the ones on Amazon, they do come in packs so you'll get more than just the four left in the universe. )

If someone could post a screen grab or two for reference it would be great. It would also help confirm the size, since each gemstone in the concept art has a different shape their dimensions aren't exactly fixed at 25mm. It looks like they've just used the max. length of that "gelcap pill"-shaped one for the 25mm size. Those others are smaller, so something, even the gemstone in Young Grant's hand would help with the size.

Dino.

I have to watch it on iview & it won't let me take a screen shot. I hope someone else can grab some. :-(

Here you go

We only see it for a moment and, annoyingly, it rolls in Grant's palm so most of the frames are blurred. I keep trying to upload a gif of this but despite trimming it down to 1.5MB I'm still getting an error that it's too large

Found this on the net:
Critical Hit LED D20 Die
http://www.thinkgeek.com/product/deaa/


Found one on eBay for $13.00 USD

You could just buy a set of these....

http://www.ebay.co.uk/itm/MTG-RPG-D-D-DND-Poly-Dice-Board-Game-set-of-7-sided-die-D4-D6-D8-D10-D12-D20-Hot-/172381301584?var=471208373787&hash=item2822b9eb50:g:UfwAAOSwHMJYCJk6

BioDoctor900

Nice job there Vale, great snaps, & Nate nice find with those dice, cheap too, I wonder how easy it would be to remove the numbers? I might get a set & try, next pay. will let you know if I do & how it goes.

The set Vale found probably have a deeper Bas-relief for the numbers - but also probably closer to the size shown in the series. I guess I can try the orbital sander and see if the numbers can be removed on the die I ordered.

What we really need to do is find 20 sided geodesic gummies. 

Thanks for those screen grabs, Vale! They at least help with the sizing, and it looks like it could be one of those dies like Nate posted, but with its numbers buffed away, leaving a plain red polygon.

Quote from: Vale on Dec 28, 2016, 12:37 pm
I keep trying to upload a gif of this but despite trimming it down to 1.5MB I'm still getting an error that it's too large

Unfortunately that's because if it's an animated GIF, inside the GIF are TIFF files, and not only does the Forum not accept TIFF format images, even though your GIF says it's only 1.5MB, each TIFF within it is actually much larger. (I've got a simple GIF with only two files in it. The GIF reads as 17kB, but each TIFF inside that GIF is 3.3MB. Don't ask me to explain it any deeper than that; I don't know how it works out that way. It's just one of those things I discovered while trying to trim down a GIF a while back.)

So there are two forces working against you: the TIFFs being huge in filesizes, and the Forum not accepting TIFFs.

Thanks again for the grabs, and I hope I've explained why you can't post the GIF.

Dino.

I've ordered my set, now to wait for them to arrive from the U.K. in about 10 - 14 days.  

**EDIT** Oops, make that Hong Kong & 4 weeks for delivery. they send by sea, not air, on the "slow boat from China".

I just received my "Dice" 2 weeks they took, not bad for Hong Kong, well the numbers are molded into the dice, so I'm trying to scratch the white paint out, using a small jewelers screwdriver. We'll see how we go. Don't like my chances after trying for 10mins so far.

The one in question is about 23mm point to point, measured with a vernier caliper. There's also the Dodecahedron that measures about 20mm.

I'll let you know how I go.

Chris.