Gem silica

[cabby]

With the amount of work I am looking at to fix up my own saws I decided to just buy a saw for water rather than build one. Been looking through my rough to figure out what size is needed and found that the inspiration mine gem silica will be the deciding factor. 

anyone have experience with cutting this material? It LOOKS like the pattern goes every which way but the edges are rather crumbly. Is there actually a direction to follow with this material? This chunk is 4x5x2.5, so cut angle is the deciding factor of what size saw I need.

On the other hand, I have no clue if this rock is “gemmy” enough to be worth a more expensive saw! Hard to get good pics of it but I see a fair amount of transparent blues and greens at the edges. Need to buy a good flashlight for pics since I can’t really take a pic when using the flashlight on my phone lol.

I have no qualms about buying a larger saw for water if this rock is worth the bigger faces, but if this material is pretty meh anyway… you get the idea. 

[cabby]

My poor retinas! I do NOT recommend doing this!!!

the work light shows the translucent areas better. Looks green in the pic but the corner on the right normally looks blue. think that is the purest blue area but hard to tell how large it is.

[cabby]

While examine it I noticed that around 1/4 of the rough is primarily gem silica with small inclusions. Worth cutting off to treat as a separate material? Or included stuff isn’t worth much? Hard to find info about inspiration mine material specifically. If it’s best to cut that off then the remainder of the rough would be a smaller size, which reduces the size of saw needed, I guess.

[lapidary1234]

I had some material similar to that stuff once. In particular the bottom right of the first pic makes amazing cabs that take a nice glossy polish due to the high silica content.

Regarding which saw to use, for a stone that size I would use my 14" slab saw. I *think my 10" could manage it but that is larger than I like to cut with a trim saw. You would have to accept that you'll lose some of the material but you'll lose some regardless, imo I would just use my slab saw for ease of operation.

Haven't heard of the inspiration mine but the gem silica I had that looked similar was supposedly from Peru.

[cabby]

lapidary1234 do you cut yours with oil or water? I’ve read that you should only use water for chrysocolla and malachite, which are in this rock. I have an 18” oil saw but zero water saws. Having a heck of a time figuring out if this rock is even valuable enough to be worth basing my next saw off of! The vast majority of similar gem silica (inspiration, ray, morenci) either don’t show backlit photos or the photos show virtually zero hint of gem silica in them, so not really comparable to determine value.
Remembered that I have a baggie of offcuts/preforms of this so looked through those. it seems like almost every piece has at least some transparent blue, and about half of them are at least 30%. Still wondering how good that corner is but won’t know unless I cut it out. Looks like maybe 250g worth of gem silica but not clue how pure it is.

[cabby]

Btw it’s entirely possible that I am misunderstanding what I am looking at! I honestly thought this was some weird man made rock when I found it (thank you to those of you that told me otherwise!) so all I know about gem silica is what I’ve gleaned through a lot of searches and YouTube. 

if I’m doing the light test wrong or misinterpreting what I am seeing, someone please tell me! First two pics are some of the more gemmy offcuts.





these are some of the lesser ones, what the majority of pieces are 

[gunsil]

I cut chrysocolla and malachite in oil often. As soon as the cut is done I toss it in the kitty litter, let it sit for a day or two and then put it in a small tub where my washing machine empties and let the hot/warm soapy water from a load of laundry wash it. Never have had a problem with the oil. That piece you show only has some smaller gem silica in it, I have some similar material, very hard to get large pieces of gem silica from it.

[cabby]

Sept 20, 2024 7:58:22 GMT -5 gunsil said:

I cut chrysocolla and malachite in oil often. As soon as the cut is done I toss it in the kitty litter, let it sit for a day or two and then put it in a small tub where my washing machine empties and let the hot/warm soapy water from a load of laundry wash it. Never have had a problem with the oil. That piece you show only has some smaller gem silica in it, I have some similar material, very hard to get large pieces of gem silica from it.

Is the gem silica not worth thinking about unless it’s larger, pure pieces? Hard to get good pics of it (can try outside later, and actually wet it this time!) but there’s an area that has a pretty hefty amount of gem silica in it. If I was aiming for PURE pieces without inclusions those would end up fairly small. The off cuts seem to have been taken off of the larger faces while the gem silica goes deeper, so not a lot visible in those.

[cabby]

Finally got off my bum and took some pics outside. Sorry for so many pics! Can’t decide which are most useful lol. Now that I bothered to wet it I can see that while there’s a good base of gem silica it’s not “pure”, would have a lot of inclusions no matter how I cut it. Might cut this rock in half and price the slabs from this section higher than the less gemmy zones. Guessing there’s not much call for gem silica with inclusions so probably not worth treating it as an entirely separate material, just as a different grade. Not that I’ve had much luck finding similar enough comparisons…








thread ended up waaay off topic now! My original question of if I should choose a saw size just for this is moot since it seems to be fine with oil, but now I’ve already started down the rabbit hole of trying to figure out the value of this material…

[AzRockGeek]

That is a beauty, I wish it was in my collection. There is no way I would cut it, you could not replace it.

[cabby]

Sept 20, 2024 15:21:09 GMT -5 AzRockGeek said:

That is a beauty, I wish it was in my collection. There is no way I would cut it, you could not replace it.

I feel that way about pretty much each and every individual chunk of rough! Forcing myself to cut things has been extremely difficult since I am terrified of doing bad cuts on things I may never see again (and unlikely to be willing to pay enough if I do).

[jasoninsd]

Sept 20, 2024 15:28:54 GMT -5 cabby said:

Sept 20, 2024 15:21:09 GMT -5 AzRockGeek said:

That is a beauty, I wish it was in my collection. There is no way I would cut it, you could not replace it.

I feel that way about pretty much each and every individual chunk of rough! Forcing myself to cut things has been extremely difficult since I am terrified of doing bad cuts on things I may never see again (and unlikely to be willing to pay enough if I do).

SLAB THE CRAP OUTTA THAT PIECE!!


There's a cab I made from that same material in this thread:


forum.rocktumblinghobby.com/thread/105993/got-cabochons-week-28-24

[cabby]

jasoninsd so pretty! I’ve noticed that the vast majority of this stuff on the market doesn’t have gem silica in it (glad you are on of the precious few that don’t call those gem silica!)

mine seems to be the original of this material, which DOES have gem silica. Guessing that most of what’s left on the market is the leftover material after all of the gemmy bits were used up. These are just OFF CUT pieces I found, but haven’t seen any hint of a piece he processed.





I do plan to slab it eventually, think it will be a good seller, but need to figure out HOW lol. Might have to just cut it in half and decide from there which direction to be cutting. 

Btw this stuff is insanely difficult to take pics of! There’s so much going on and can’t capture on camera what I can see with my eyes.

[lapidary1234]

cabby I'm not sure what to tell you regarding slabbing it but I can tell you this....

While an unpopular opinion im sure, I run my 14" slab saw with "gem lube" from kingsley. It is an additive type coolant, mix 1 part gem lube to 10 parts water. I haven't noticed any problems with using it. But I tend to not do everything as stated as popular opinion. I try and see for myself. In fact I've been advocating the cheap kingsley notched blades as well. I've had the same notched blade in my 14" saw now it will be a year in October. It cuts just fine!

Regarding the gemmiest of gem sections I would suppose you'll have a hard time isolating and extracting just that. Honestly though unless you have a customer who commissioned a piece requesting it I would keep the inclusions in the piece. I personally love the interplay of the malachite/chrysocolla/silica sections!

But I can understand you wanting a (small) cab of the purest stuff! I have a piece of gem chrysoprase that I paid $1/gram way back around 2000 when I first got interested in lapidary. The guy (who was not wrong) selling it told me its incredibly hard to find stuff that gemmy. Years later and taking a close look at it even at A grade a it has some veiling (inclusions).I would have to suppose a piece with zero inclusions wouldbe considered AAA grade!

I'm gonna have to do some deep digging, I know I took a picture of one of the cabs I made of the gem silica I had...I feel like the cab itself is around somewhere as well but where is anyone's guess. Thats what happens when you're short on space and long on rocks

I'll reply if I can find it!

[lapidary1234]

Okay, after looking I can't find the cab I'm looking for or the picture I know I have somewhere. I did find a couple of really old and blurry and pixelated pictures of it and another piece of the same material. I'll post them but am unsure how they'll display

I'm unable to find the piece of gem chrysoprase either but I found a couple of pics of not so gemmy chrysoprase that I left some of the matrix in rather than try and cut around it all. I personally think it adds to the overall appearance.

Again, sorry about the blurry pics. I was able to find one small piece of it in my display cabinet and tried taking some better pics so here is another piece:




Thank you for making me dig around through old pictures! I found some real goodies of my friends and old rocks. Its amazing how many stones I've casually sold or gifted over the years, definitely surprised me seeing old pieces I hadn't thought of in years. Equally amazing is how far the camera technology has gotten on out phones

On a side note, I was able to find a digital microscope/camera and just ordered it today, oh how I eagerly await being able to take photos at that scale!!!

[cabby]

lapidary1234 WOW! Thank you so much for the pics! It’s super useful seeing what others have done with similar material since Google search only wants to show me the cream of the crop or listings. I kept rereading the price you paid for chrysoprase… yikes! This guy had very few gemstone type things, just some coober pedy opals and a yet unidentified tiny something (swear I will figure it out someday), so I haven’t been thinking in gemstone prices yet! Been having a hard enough time figuring out the darn slabs lol.

Knew gem silica is valuable so figured it might be worth isolating, but no clue what the prices would be. The gemmy areas would be more like the final pic you showed, wouldn’t be able to avoid small opaque areas (crysocolla or malachite in this case, no host on this rough) or at least sections of uncolored chalcedony in each cut stone. The videos I’ve seen treat gem silica more like gemstones, grinding away at a chunk to find the best bit vs preform from slab, so no clue how I would even cut or sell this! With all of the malachite and chrysocolla bits I guess this is cabbing grade, not faceting. The entire rock is 960g with the mostly gemmy area being probably 200-250g? So if working from slabs could get a fair number of cabs like last pic, and quite possibly a few that size pure gem silica, but won’t know until I try isolating it. The rest of the rough is so large that I can’t get a good look at it.

As fun as it is to look through these things, I’m starting to get a bit sick of rough that is so rare these days that I can’t find comparable products online 😆

[victor1941]

Cabby, I am showing several pictures for cabs made from material similar to yours.
Plume malachite
?

[cabby]

victor1941 those are beautiful!! Thank you for sharing those. While it may not be as premium as pure gem silica, your examples show that the inclusions make for beautiful material as well! Personally, I think I prefer the inclusions more than pure gem silica!

[victor1941]

Cabby, this is another set that shows more blue.

[cabby]

victor1941 it looks like you’ve worked with this type of material a lot! Those are all quite beautiful! And it shows that there really is a market for the gemmy base with inclusions. After seeing your pics I am leaning heavily towards isolating the more gemmy areas and selling those slabs at a different price than the less gemmy pieces. I had been focused on this specific material or similar mines and completely forgot that there are things like needles blue that are gemmy with inclusions!