How big is too big?

[raynebow]

hello, i''m new here, i was just wondering, is there such a thing as too large of a stone? at what time would a stone reach this point?

i have an odd sapphire rough gem i recently aquired, it is roughly the size of a small/medium chicken''s egg, seemingly encased in a off-orange yellowish cacoon, whether this is true or not im not sure, as i am no gemolgist. yet in places a vibrant blue peeps through, and using a handy dandy hand tool i managed to take about .5 mm off of one spot near the middle of the stone to find it becoming more and more blue as i went...

back to my original question, would this be a stone considered too large to work with?

also, can anyone tell me whether this orangy-yellowish coating is normal for this type of stone, or if that is ''probably'' the way it is all the way through?

 

[Nicrez]

Without getting into too much technicality let me try to answer (or ask) some questions. First know that Sapphires are in the Corrundum family of stones, meaning (along with Rubies) they are the hardest stones, after the Diamond...

1) Is it too big? Perhaps for some cutters to create one large faceted gemstone, but that can easily be cleaved and made into several gemstones, depending on how good a lapidary the person is, depends on how much of the stone will need to be cut away.

2) How do you know that this specimen is Sapphire? Have you had a professional or appraiser look at it? I say this, because Sapphire doesn't normally come in round shapes, and is usually found in barrel shaped hexagonal crystals. Some can be found as pebbles, which are smoothed, so that is a possibility.

3) Where is it from? If it truly is a Sapphire, the origin (Kashmir, Burma, Ceylon, Australia, India, Montana) of the specimen will determine the value. The color, the clarity and other such items can be also useful to know, and if the specimen can indeed be cut at all, or if there are too many fractures and internal flaws to even be worth cutting is important to know.

4) You should know that it is likely to find larger "commercial" quality sapphires, but the "quality" large stones are much more rare. A good cutter can make sure that the color of the stone is also shown properly if they know how to, because sometimes the color of the Sapphire can be concentrated on the outside, or there can be zones of stronger color in the stone. Knowing how to cut it well, can make the difference between a blue stone or a washed out light blue.

5) I have never hear of a yellowish-orange coating, is it like a stone coating? Is it dirt? Sapphires are usually found within a larger rock matrix, or it could possibly be magma covering the stone, perhaps?

6) What tool are you using? I suggest not making holes int he stone if you are looking to facet it, so that it does not damage the stone. I highly suggest bringing it to a gemologist appraiser who can test the stone without making any more holes, and could give you an approximate worth and origin.

Good luck!

 

[raynebow]

the stone.

 

[raynebow]

another view...the back.

 

[raynebow]

close up.

 

[raynebow]

last one.

 

[Richard M.]

Hi Raynebow,

That's what I call an interesting FLR (Funny Lookin' Rock)

. It shows strong evidence of being blue corundum (sapphire) but it would sure help to know a little more about it.

1. Where is it from? I'm going to guess North Carolina just to get things going, and I could be several thousand miles off the mark. The source is important because a lot can be determined from it.

2. When you hold it up to a strong light is the blue area on the edges transparent or strongly translucent? That's a very important clue about what kind of stone could be cut from it and its value. For instance, if it's transparent then it possibly could be faceted. Judging from your images it would have to be sectioned into smaller stones because the rough appears too thin to cut a single large faceted gem. On the other hand if it's opaque to translucent maybe a single large cabochon or carving could be made from it.

3. Does it have any obvious fractures or internal imperfections? I notice one area that seems more gray than blue. If the stone's translucent use a hand lens to determine if it has tiny included crystals that make it appear "silky." If so, that's a sign of potential star material that might also be heated to make it transparent and improve color.

I hate to stick my neck out without actually seeing the stone but from the images I'd hazard a guess it's more suited to carving than faceting -- but images can be very misleading. I may be able to recommend a local expert who can advise you better if I know where you live, or at least the general area.

Interesting stone!

Richard M.

 

[DiamondExpert]

Well, I'll stick my neck out - don't quit your day job...carving or paper weight is the way to go.

 

[rubydick]

Raynebow,

I'm afraid I have some bad news. Yes, your stone is a blue sapphire, but it has no value as a gemstone.

What most laypeople do not understand is that not every rock is a gem. Gems are only the most perfect of minerals. They are extremely rare, which is why they are valuable.

For more on the subject of the value of big pieces of corundum (and other gems), see this article:

Big Time

You asked about the orangy skin. Actually, there is no skin. The brown stains are caused by iron-oxide entering the many fractures that this piece is riddled with. Given time (millions of years), such stains will entirely penetrate the stone.

The major difference that separates gems from also-rans is clarity. Most crystals do not have the clarity to be useful as gems. The piece in the pictures above is a textbook example. It is virtually opaque. Fine gems will be transparent, or nearly so.

 

[raynebow]

still no chance it may yeild a small semi-ok piece somewhere in it that could be usable fora nice pendant or something? oh well, it does make an interesting conversation piece anyway

as for who was asking over it, i dont remember exactly where it was from, somewhere in south america, i think.

thanks for the advice on it btw, guys, i wasnt expecting it to be worth anything, was maybe hoping for a nice carving or maybe a small bit for a pendant heh. hey now that it's pretty much stated finding a significant piece that isnt highly flawed, perhaps i can find someone to do both, make a nice blue carving piece for a pendant with it heh. something interesting... for my baby neice heh.

 

[yowahking]

There are many materials like the sapphire family where the carving and novelty quality can be very large chunks. There was a scam several years ago where a guy claimed to find a million dollar star sapphire in a pile of rocks at a gem show. It made big news everywhere. Later it was found out that he had shown the stone to many gemologists months before the "discovery". All but one decided it was basically worthless, although interesting for it's size. One idiot gemologist decided it had a million dollar value and it was to be used to make a large tax write off to donate it. Jade is another such gem. Some chunks can be made into a table top that costs very little money, while other pieces can be worth thousands for a piece the size of a chicklet.

 

[rubydick]

Raynebow, sorry, no chance your rock is worth much of anything.

Scott, the "idiot" gemologist you mentioned apparently wasn't just lacking in smarts; rumor has it he was involved in other questionable appraisals