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Post by Starguy on Jan 24, 2015 19:36:39 GMT -5
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Post by braders on Jan 24, 2015 20:33:02 GMT -5
Wow !!!!!
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jamesp
Cave Dweller 
Member since October 2012
Posts: 36,612
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Post by jamesp on Jan 24, 2015 22:07:10 GMT -5
Those are monsters. Wild color too.
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Post by Pat on Jan 25, 2015 0:02:45 GMT -5
Wow for sure! Lucky you!
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Post by Starguy on Jan 25, 2015 0:16:41 GMT -5
When polished, they show stars. They're hard to photograph but all of the polished ones have a star.
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Post by Pat on Jan 25, 2015 0:25:15 GMT -5
Are they all purple?
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Post by Starguy on Jan 25, 2015 0:59:15 GMT -5
Hi Pat. Haven't heard from you in awhile. All of those corundum crystals have that purple/silver color. They don't polish really well but they are cool because they are big. They get carried in my pocket more than most of my other rocks. Nothing makes me happier than a good pocket rock. |
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Post by 1dave on Jan 25, 2015 7:14:32 GMT -5
Hi Pat. Haven't heard from you in awhile. All of those corundum crystals have that purple/silver color. They don't polish really well but they are cool because they are big. They get carried in my pocket more than most of my other rocks. Nothing makes me happier than a good pocket rock. I bought 20 pounds of them back in the day (about 1965) and spent hours putting drops of oil on them to locate the best stars. I purchased my first (and last) tumbler to make that task easier. All went well until cleanup time. MUCK! Not knowing a thing, I decided to just rinse as best I could and put them back in the tumbler with fresh water. Beat the hell out of them! Get them almost perfect and the surface orange peels off! I got caught in a cash bind and had to sell them all. Now I wish I had them back and a little common sense. |
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Post by snowmom on Jan 25, 2015 8:16:01 GMT -5
beautiful- how cool that they came down through the family, too. Your love of rocks must be genetic!  |
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Post by gingerkid on Jan 25, 2015 10:39:18 GMT -5
That's an awesome inheritance and those are beautiful xtals, Starguy!!  Your grandfather was a rockhound, too? Did he cab and/or facet any of his findings? Do you plan on keeping them as specimens? Haven't seen any corundum from Idaho and thanks for sharing them with us.   |
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Post by Starguy on Jan 25, 2015 11:54:02 GMT -5
gingerkid. Jan, they're too cool as crystals to do much to them. I polished the end on a couple so the star could be seen. One got cabbed on one side and flat lapped on the other side. You can see crystal growth planes on the flat lapped piece. My grandfather tumbled, cabbed and faceted. I still have his old facet machine. It still works OK but it's not as accurate as modern machines. That flat lapped corundum crystal was cut on that old facet machine. I haven't done any Faceting for a while. Might need to give it a go again one of these days. I need to retire so I can have more hobby time.
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Steve
has rocks in the head
Member since June 2005
Posts: 506
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Post by Steve on Jan 25, 2015 12:20:33 GMT -5
gingerkid. I need to retire so I can have more hobby time. Hear hear!! I've been thinking that for years myself. Three more years to go for me. |
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Post by gingerkid on Jan 25, 2015 14:12:56 GMT -5
Glad you have your grandfather's faceting machine, Starguy! Maybe you could make a couple of adjustments/modifications to it and use it? Do you some of his faceted gems? |
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gemfeller
Cave Dweller
Member since June 2011
Posts: 4,064 
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Post by gemfeller on Jan 25, 2015 14:23:53 GMT -5
Very nice collection Brent. There are several locations in Idaho that yield (or maybe past tense "yielded") corundum crystals of varying qualities. According to one source the Burgdorf corundums once were so abundant they "boiled" the gold miners' sluice boxes, interfering with gold recovery. A close friend and mentor, now departed, found some of the finest black star sapphires I've ever seen at an undisclosed Idaho location. While he was amazingly generous otherwise, he kept the sapphire source a secret. It, and an Idaho location with good green grossular garnet (Tsavorite) potential, have gone to the grave with him.
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Post by drocknut on Jan 25, 2015 14:24:40 GMT -5
Beautiful crystals and a great history to go with them.
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gemfeller
Cave Dweller
Member since June 2011
Posts: 4,064
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Post by gemfeller on Jan 25, 2015 14:35:10 GMT -5
Dave and Brent: re: sapphire polish
I don't know if this holds true for cabbing but in faceting "orange peeling" in corundum takes place at a certain point in sanding. If memory serves (it's been a long time since I cut any) I think 3000 diamond is to be avoided. IIRC most faceters skip from 1200 directly to 8000.
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Post by Starguy on Jan 25, 2015 17:48:27 GMT -5
gingerkid. I need to retire so I can have more hobby time. Hear hear!! I've been thinking that for years myself. Three more years to go for me. Hi Steve Three years isn't too bad. I'm eligible in October 2016. I don't think I'll be able to afford it then though. Probably have to go till 2022. Then some rocks are going to get ground. Thanks gemfeller and drocknut. I'm pretty proud of those crystals. A co-worker of mine found some corundum crystals in the Floodwood State Forest of Idaho. They were decent crystals but only suitable as specimens. They were white on the outside and midnight blue in the centers. I never could find the location he said he found them. Apparently it was in a road cut but there are a lot of roads out there. gingerkid. I didn't inherit any of my grandfather's faceted stones. The facet machine actually works pretty good. It's just hard to get all of the facets to line up good. Could be operator error too.  |
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leadbelly713
starting to spend too much on rocks
Member since June 2011
Posts: 104
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Post by leadbelly713 on Jan 28, 2015 12:24:18 GMT -5
Most of the sapphires I've seen from the Burgdorf & Warren areas were cloudy grey to clear to corn flour blue, although I've heard a lot of gem quality material came out of that area back in the day. Your purple ones are a first for me. Definitely a nice keepsake.
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Post by Starguy on Jan 30, 2015 18:25:01 GMT -5
leadbelly713all of the corundum I have are kind of lavender to silver colored. Definitely not facet grade but the big crystals with a star on the end are cool. The geologists where I work always drool over them when I bring them in to work. I saw some corundum in a mineral museum in Rapid City that had crystals around 18 inches long. I can't remember where they were from but I'm guessing montana. I've polished and re-polished them but you can't get a good finish. Too many inclusions and natural crystal fractures. My theory is that they were formed deep underground. When the pressure is released by erosion, the internal pressure causes them to crack. I'm guessing the same thing happens to our local garnets. It's rare to find one without visible cracks. thanks for the information. The more I learn about the location, the cooler they seem. I would like to go down there one day and look around. You never know what you might find. I don't think anybody has been mining them for years. One or two good floods can turn things over in a hurry.
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Your grandfather was a rockhound, too? Did he cab and/or facet any of his findings?
