Thursday, January 27, 2011

Emeralds: Before the Oil, After the Oil, and After That

So my gemstone dealer D. and I decided to conduct an experiment.  It was an ancient one, and he’s done it before of course, but I never had: we tested how an emerald would change if it got oiled.  Oiling emeralds is as old as the hills, and it is common practice.  Most emeralds on the market are oiled – an eye clean emerald that hasn’t been oiled is a rarity.  I’ve read that cedar wood oil is a commonly used filler, but D. uses linseed oil, and a friend of his uses canola oil.  The oil seeps into the stone through the cracks that reach the surface, thereby masking some of the flaws.  Over time, the oil dries out and the cracks get exposed, but the process can then just be repeated.  It is also reversible: if you want to get the oil out, just submerge it in acetone or denatured alcohol for a few days. 

For our experiment, D. temporarily sacrificed a matched pair of 6mm round emeralds that he cut himself.  Now the oil D. uses (but only when explicitly asked to enhance a stone) contains green dye.  That’s technically a “no no” in the industry.  Only colorless oils are considered acceptable, though who knows how many people also use dye.  Here’s a picture of his oil:

Dyed Linseed Oil

D. heated up the oil a little in order to liquefy it more.  He also warmed up the stones a tad over a flame (but not too much, as they can fissure).  That way, more oil gets into the stone, he claimed.  This is how the emeralds looked before submersion:

Emeralds Before Oiling in Fluorescent Lighting
We left the emeralds in the oil for a week, then D. took them out and wiped them with a cloth.  I’ve often seen D. throw one of his gems into alcohol for a little while before presenting it to a customer.  That way it is squeaky clean (it also signals that the gem wasn’t oiled).  In this case, he refrained from doing so of course. 

Upon visible inspection, the stones had actually brightened up a bit.  We were expecting them to darken because of the dye, but because this pair had a fair number of inclusions that were filled, and as a result they actually looked lighter (because more light could pass through would be my guess).  You can also see – a little bit at least – that the number of black inclusions in the stones visibly lessened.  My photos were not all taken in the same lighting conditions – I tried but it just didn’t pan out – and my camera isn’t the best, but I think you can tell the difference.  Look especially at the stone on the right.  It has a black line on the right top which has vanished in the second set of pics. 

Emeralds After Oiling in Sunlight

Emeralds After Oiling in Shade

Now, D. wouldn’t want to sell an oiled emerald, so we had to get the oil back out.  Also, I thought it was instructive to show that his can safely be done.  So I put the stones into denatured alcohol for a couple of days, then just wiped them dry.  I think they should be left in there some more, but already, you can see below the one larger black inclusion has re-appeared (the stone is on the left this time) and the coloring is a bit more grassy again. 

Emeralds After Submersion in Alcohol, Photographed in Shade
 Naturally, you cannot conduct this experiment with an emerald that doesn’t belong to you, and if it does belong to you, you may be in for a disappointment after getting the oil out (if you bought the stone from me, go ahead, nothing bad will happen).  Incidentally, you also don’t want to clean an emerald ultrasonically; it has the same effect.

But when you buy an emerald, there are couple of things you can do:
1) Ask about treatments, and ask specifically about oil.  In the worst case scenario, the seller won’t know.  But what he does know, he has to disclose.  Most likely, he will say that the stone has been oiled.
2) Loupe the stone, look for an oily film, or ask the seller to clean it in alcohol for you.
3) Under the loupe, look for cracks that reach the surface.  The fewer such cracks there are, the less likely it is that the oil has changed the gem very much. 

In terms of value, you get what you pay for: a heavily oiled stone has less value than an un-oiled one.  Oiling changes the stone somewhat, but not drastically, as you can see here.  Other fillers (epoxy and polymers) can achieve more dramatic changes.  Those definitely need to be disclosed to the buyer, and if you can, stay away from them.  A totally untreated, eye clean and richly colored Columbian emerald of even half a carat should cost you about $500 wholesale, so that gives you an idea.  And good luck finding one!  The emeralds I have, beautiful and sparkly as they are, all have at least a couple of inclusions that are visible to the naked eye.  Some of my low grade cabochons are opaque (but I’ll sell those for much less).  Also, the lighter stones, while they have less value in terms of color, are also cleaner and so they have higher brilliance.  I prefer the slightly lighter ones for some reason, but this is really a matter of taste. 

Wednesday, January 19, 2011

Garnets and the other Garnets

January is garnet month, or so the Jeweler’s Association says, at any rate.  And if you are thinking red or pink garnet, then this would be a very short blog entry.  It would end right here.

Luckily, garnet is a lot more interesting than that once you get away from the reds.  While there are, supposedly, a lot of distinctions to be made with regard to red garnet - pyrope, almandine, rhodolite - in the words of my favorite gemstone dealer, D.:

“It’s all the same stuff, it comes from the same places and it gets mined by the truckload.”

The good stuff, in my opinion and in that of many others, are Spessartite and Mandarin garnet, Tsavorite, and Demantoid.  Most of these are found in Africa, mainly Kenya and Tanzania, but now also Nigeria (Demantoid and Spessartite also occur outside of Africa).  And all of them are recent additions to the gemstone market.  Insiders think that these garnets are now where Tanzanite was thirty years ago: they are already fairly hard to find, but still reasonable in price because the mass market is barely aware of them.  But give it time and this will change. 

Garnet is also interesting is that it is never treated.  It doesn’t need it, for one, and secondly, none of the treatments that have been tried have actually enhanced the way it looks.  So there hasn’t been any point.

1. Spessartite and Mandarin garnet: the distinction between these two is fluid.  The lighter more orangy stuff is called “Mandarin,” the darker, more brownish gems are Spessartite (named after the Spessart forest in Germany where it was first found).  I’ve only ever seen Spessartite and some very heavily occluded Mandarin.  But garnet should not have a lot of inclusions, consequently, that stuff is very cheap, starting at perhaps $8 a carat.  The nicer stuff trades for 10 times that or more.  Larger sizes (say 3-10 carats) are around at the moment, but as with all gems, the price per carat changes with size.

Tsavorite Parcel from Nigeria

Anecdote: when I bought my first larger Spessartite parcel last fall (see picture above), the dealer quoted me a ridiculously low price.  I saw that his tray contained rather a large number of bigger size pieces.  So I asked if he was sure about the low price.  He said “yes” and so I took out all the big and clear stuff.  I could tell he was not happy, but a price is a price.  At the end of the transaction, he said: “you know you got a good deal.”  He was right.

Periodically, I list Spessartite earrings and rings on my site.  They all come from that dealer.  If it is at all your color, I recommend these to you as among my very best buys.

2. Tsavorite: these belong in the Grossular garnet variety, where Grossular is the occluded, non-gem grade stuff, and Tsavorite the clean stuff.  It is named after Tsavo National Park in Kenya where it was first found.  Already, Tsavorite is traded at a significantly higher price than Spessartite, and anything over a carat is hard to find.  Considerably more durable and cleaner than emerald but similar in coloring, Tsavorite is a great buy.  The darker colors are more highly valued than the lighter ones, but the medium green ones I offer out in my stud earring sections are a good buy.  The Tsavorite in those earrings are not the very best available, but they are an excellent value for the money.  I will try, this spring, to get some other, larger pieces.  But they will definitely cost more.

Tsavorite Garnet Stud Earrings

3. Demantoid: this is the most expensive garnet variety, and the only color I’ve ever actually seen it in is an olive green.  Demantoid is very clear, and comes in all green varieties from more yellowish green to more emerald green.  I don’t have any because it costs even more than Tsavorite, so there’s no point for me to stock it.  The olive colors are cheaper, but not as nice, the good stuff, again, is the clear stuff with fewer yellow overtones.  Wholesale prices are $100-$150 per carat for the small sizes.

2.55ct VVS-VS Demantoid Garnet
Demantoid Garnet Parcel from

Wednesday, January 12, 2011

New Ideas for a New Year

After a first full year on Etsy, I have lots of new ideas, and I want to drop those ideas that didn’t work.  Here’s a first stab at my plans – any suggestions and ideas are most welcome!

1. More gemstones and gemstone designs, fewer wire wraps.  Sad but true, wire wraps and beaded designs don’t sell very well on Etsy.  So I’ve deleted my wire wrap earring section and replaced it with a hoop and dangly earring section that will focus on set stones, not beads.  I’m actually very exited about this, because it lets me use my gemstones in a whole new way.  I will work with both 14K and sterling hoops, and I will provide several design options for most listings.

Blue Topaz Hoop Earrings

2. Free earrings with wire wraps.  I’m not a matchy matchy person, but insofar as my wire wrapped earrings have sold at all, they have sold as complements to the necklaces.  So I’m giving them away.  Consider it a “wire wrap stimulus package”.

3. More squares.  My single best selling gemstone cut last year has been the princess cut, with baguettes running a close second.  So I’m going to try my best to find more of those.  I have some amethyst ready to go, and green tourmalines in the works for earrings.  Garnet, peridot, and citrine are fairly easy to get in princess cuts,  and I think I can also find another princess cut emerald.  And baguettes for rings.  Soon to be listed are a pink tourmaline, an aquamarine and a blue zircon ring using baguettes and emerald cuts. 

4. More rings.  Rings are my best selling item on Etsy, right up there with post earrings and of course, the never ending tie bars.  So more rings it is, low end to high end price range.  I’ll go for some larger stones as well, as many of you like those.  But note that this will either mean higher prices or less interesting gems.  Emeralds, rubies and sapphires, untreated and natural, are pretty affordable in the larger sizes.  I am also working on some more melted rings – I love them, and I’ve gotten a few sales (as well as many complements) out of them during the holiday season.

Blue Zircon Baguette Ring

5. More 14K gold.  Prices for gold are through the roof, so this is going to make some items more expensive.  But my main idea is to use some 14K gold beads as accents, and 14K gold bezels or settings for the rings.  That will keep the cost manageable.  But note that a 14K setting can cost me anywhere between $15 and $50.  Prong settings cost less than baguettes, and full bezels are the most expensive.  The 14K gold beads are not so bad in price, but they take time to add.

6. Clearance items.  What doesn’t sell must go at a lower price.  I’ve lowered the price on some of the items that have been on Etsy the longest.  It you want something out of that section but still think they’re too expensive for you, make me an offer.  I’d rather see the items worn than wasted.