Test Cutting Star Garnets

okay i think it's time to talk about star garnets a little bit today where if you've seen my previous video from almost a year ago now i talked about how to best cut into star potential star garnets to try and find you know where the star might be it's my most popular video by far and there's quite a few comments on there that are both helpful and not very helpful some of them have been trying to suggest you know what you do and one of the suggestions was to make a sphere out of the star garnets and essentially cut in from the outside make it all the way round and polished and then that way you can see where the stars are and then from there you cut into it and use that to line up where to make the star and i thought that seemed like a lot of work to make a whole sphere out of these and then do the work from there which i guess if these are really precious then you know maybe you need to do that work in order to preserve as much material as you can i thought i would do a little test to see you know just how many of these star garnets would actually star from the emerald creek locality in idaho and what i did was went to the local lapidari workshop mike's shop and i took i think i ended up with about 12 star garnets that i selected based on you know they have good crystal faces or they were big basically what i've heard from a couple sources is the bigger they are the more likely they are to star and there are a couple of forms of garnets where there's the ideal you know dodecahedron where you got the 12 crystal faces that are if the crystal is whole there they look really nice but there's also a kind of crystal varieties that are more twinned and might have 24 sides rather than 12 and i read from one source that these are less likely to star and so i cut a couple of those my initial results were not very promising these are the cut faces that i actually worked with these are the off cuts so some of them are too thin to do anything with or really busted some of them i might be able to actually work with in the future and maybe get a star on the other side so you get two stars for the price of one stone which is nice and my initial test was to cap them down do a a light dome shape and from there grounded on a 60 grit wheel and then ground the kind of rough edges off with a 600 grit wheel and from there i didn't see any stars which was really disappointing especially when a lot of these have what i would think to be our more characteristic patterns on the inside in some of these there's a hexagonal twinning that you can see from the cut face that would suggest that there was growth zoning and you know silky inclusions in there which i thought would be able to star and yet i wasn't seeing any stars on my 600 grit polished cabs or half cabs i guess they're not very domed and in order to get a good star you actually need a relatively high dome higher than a normal cabochon and that was disappointing i thought okay well none of these star that's the result you know they're not going to starve from they're not guaranteed to star from that area it wasn't until kind of got a little frustrated and went further with the polishing where took it to a 325 grit wheel to kind of get rid of these more flat areas on the stones from the 600 grit because the 600 grit only gets rid of the really coarse scratches from the 60 grit wheel it's kind of a odd process but it works really well for cabbing so we took it to a 325 wheel and obviously that was you know less polished than the 600 grit so you didn't see anything there but then we jumped up to a 1200 grit wheel and after we did that we were able to see stars and this is a one of the bigger samples and shows a star really well i think the results from that suggest that you need to get up to at least a 1200 grit in order to see a potential star in the stones and after i did that i realized i wasn't going to be able to take all of the stones that i cut up to 1200 grit so i had to kind of pair back a little bit and chose some of the better samples these ones were off cuts and i this one fell apart as i was cutting one of these is that 24-sided crystal and all of these have at least a little bit of asterism in them which is the star the smallest one yielded a pretty poor star which makes sense from what i've heard this one i was a little bit off center the star kind of crosses over in this face on this side here so it's a little bit off center but it's a decent star for the size and this one despite its size is fairly weak and that may be because i'm too close to the edge didn't have a high dome it's kind of purpley in the middle which i've taken to be a sign that it's not a great star potential i think the darker the stone on the interior the better it is because if we look at this one that had a good star where some of the twinning planes are which i think are hard to see here but it's obvious on other samples the star isn't as well defined or goes to disappears completely and it's kind of a you know dashed line pattern of a star another thing i've concluded from this is that these the ones with the raisin pattern on the outside it's kind of hard to describe but you know this is a well-formed crystal on my left hand and on the right hand it's pitted there's some etch weird pattern marks on the outside this is the raisin appearance it's the best description i've been able to find of it and these ones are almost holy black on the inside and yield really nice stars but you can see that flashing across there and i actually left this one not very well polished because the way the ray goes across the stone on this face here it actually lights up almost the whole thing in one go which i thought was pretty cool and if i wanted to try to locate the star it seems to be somewhere in the peak of the stone there where the sun is you know flashing mostly and similarly these are the stones that my wife found from the area she found i think you know two maybe there's a third one in there that's kind of small but these are the only couple of potential raisin skin stones that we found and besides the besides the outer appearance these stones are also noticeably heavier than the well-formed crystals and so if you find one that feels relatively heavy for its size that one's more likely to start up as well but i think what's interesting about this site is that i found estimates of you know 10 of these will star or you know all of them should star or 50 will star and it probably depends on where within the locality they were getting those garnets from in the first place because the forest service digs up from different parts of the creek and brings that material into the dig site and i think we had a pretty good uh locality from what i heard these are pretty good size for the area in that forest creek site at least from my results at least if you get up to 1200 grit you're likely to see at least a little bit of asterism in every stone that i i looked at now that's not going to say that every single stone should be a star garnet because there are stones like the ones that i faceted in previous videos those ones were relatively clear and wouldn't have as much silk and so probably wouldn't star but i think by and large you will get some asterism in the garnets now it doesn't mean that these will all make good stargard it's obviously you know these ones are pretty fractured there's still some polishing powder on the inside of these cracks here that are going to be almost impossible to get out some of them you know fell apart as i tried to cut them just because they're so fractured like i didn't go very far with this one because on the other side it's just a mess of fractures and if i cut down too far i'm going to get into that and it's just going to look terrible so if you want a good star garnet cabochon i think you need to look for the raisin skin appearance and the heavier garnets but it is also i think i would say the larger the stone it's worth cutting because you're going to get at least a little bit of a star if that's all you have then you know i think it's worth it to get a nice star out of it and one of the other comments i got on the video was that oh you just need to take one of these stones and cut it parallel to the c-axis and that's where you get your asterism well in garnets the the axes the a b and c axes which are related to how the crystal grows and the faces that it forms those are all equined where the c-axis is maybe a little longer than the other ones the a and b are are more equal and then it's maybe slightly elongated in one direction versus the other two you can see it's a little more blocky in that face or not in this orientation so this might be the c-axis okay so then you got to cut it parallel to that axis down the middle and cab it up but then what if you have a piece like this one where you only have a fracture a fractured piece with maybe a face there and there but it's kind of eroded away what do you do for that you know do you cab it up from the outside and see where it is those are the questions that i wanted to answer in that video and then the follow up with this one lastly i mentioned it kind of but a lot of these are very fractured and one thing you can do which i didn't do in this case i did in my previous video but before i started cutting them and looking at them closely i dipped them in muriatic acid overnight to clean out the iron clay material and the mica as well and that really cleaned out the cracks a lot and you can see a lot better into the stones how far some of these cracks go and you're able to tell you know this stone might not be good if these cracks go you know all the way through and crisscross especially with something like this where in some cases that kind of cement material maybe the only thing holding some of these pieces together which i found in my previous video was that some of them fell apart as i got rid of that matrix material so in conclusion if you want to make a star garnet from the emerald creek localities look for the raisin skin look for heavy stones relative to their size compared to other stones of similar size and you need to polish them at least to 1200 grit i think in my experience maybe someone else can see them at a less highly polished state at 600 or something if you do a really good job but i was going quick these are just a rough and ready you know cabs just to see if they did star at all i'm not really into cabs so i didn't really care about making them perfect but you know we got some stars even from some of the smaller ones not that one even from these very small ones you can get a little bit of a star which is pretty cool and this this face that lights up with the light really kind of gives me an idea of maybe you can fasten a star garnet where it's the facet falls on that plane of asterism and you can make sort of a really interesting pattern with it i don't know how you would do that but i'll look into that and see if i can do anything with it so until next time keep looking to the stars

Channel: Patrick Donohue

Views: 21,793

Keywords: garnet, gems, star garnets, gemstones, rockhounding idaho, emerald creek star garnet, star garnet, clarkia garnet, gem state, garnets, idaho garnet, idaho garnets

Id: WGgdhoMV1YU

Length: 12min 16sec (736 seconds)

Published: Wed Jul 20 2022