Color Change Gems

Color change is a fascinating phenomenon in gems.  I have seen strong color change phenomena in three stones: alexandrite, garnet and sapphire.  But there are others, such as diaspore (which I don’t think I’ve ever seen).  There are also gems that have weaker color shifting effects, depending on the angle of the light.  This is called pleochroism.  Tanzanite, tourmaline, iolite and andalusite are examples. 

Alexandrite, garnet and sapphire, can exhibit a very strong and complete change to an entirely different color in incandescent light, whereas tanzanite, for instance, especially the unheated kind, just looks different from various angles in the same light.  Depending on the gem, it can have blue, green yellow, purple and pink hues. 

Alexandrite is of course the most well known of all the color changers.  It’s also the most expensive, with a nice 1 carat piece starting at around $5000 per carat, wholesale.  Brazilian alexandrite, in my experience, often has a better color changing effect than alex from other places, changing from a strong green with teal hues to a reddish purple.  It also has a more teal(ish) daytime color, whereas Indian and African alexandrite can often be more yellow.  Historically, it is said that alexandrite changes from green to red, but I have never seen that kind of effect.  Perhaps some old Russian specimens that have since disappeared were like that.  The more affordable alexandrite usually has less of a color change effect, with the better shifting stones often looking murky and dark.  If you see a clean and sparkly gem that also has strong color change, chances are you are looking at a lab grown specimen.




My Alexandrite Parcel in Daylight





My Alexandrite Parcel in Incandescent Light

Color change sapphire usually changes from purple to pink, or from blueish purple to more reddish purple.  The effect is less striking than in alexandrite because the colors are fairly close to one another on the color spectrum.  I also own a little grey blue to reddish purple color changer from Sri Lanka.  Those are less common.  More often, you find color change phenomena in African stones, in particular, in the dark colored gems from Madagascar.  Again, the deeper the color of the stone, the more striking is the color changing effect.  Clean and brilliant stones with strong color change are not as common.  Right now, sapphire is enjoying some steep price increases, but a 1 carat Madagascan color changer is nowhere near as expensive as a 1 carat Alex (think maybe $300 per carat wholesale).



Some of my Madagascan Color Changers



Same Parcel in Incandescent Light



My Ceylon Color Changer

Ceylon in Incandescent Light

Color changing garnet is relatively new on the market, and it comes mostly from Africa, with the nicest specimens right now originating in Tanzania.  I’ve seen two kinds of color change in garnet.  There’s a brown-pink color changer, this one is much less expensive, and the effect is not always that strong.  And very recently, I’ve seen blue-purple, green-purple and reddish brown-purple effects, mostly coming from Tanzania but also from Madagascar.  Right now, these color changers are my personal favorites (although I still love love sapphire).  While on average, the effect can be a tad weaker than in Alexandrite, this is not uniformly the case.  There are some specimens with very strong color change effects.  They are also less expensive than alex right now, even though, best I can tell, they are actually more rare.  Lastly, garnet is a much cleaner stone with better brilliance than alexandrite.  The per carat price on these varies, but for a nice 1 carat piece it may be $500, for the smaller pieces it’s around $200-300 per carat.



Tanzanian Color Change Garnet Parcel

Tanzanian Color Change Garnet Parcel

In terms of treatment, all three color changers are nearly on a par.  Alexandrite is never treated.  Garnet does not respond to treatment either.  Sapphires are often heated, but for reasons that are opaque to me at this point, the color changers usually aren’t.  Perhaps the heat treatment affects the color change phenomenon, or only the nicer deeper colors change in the first place, so no heat is required.    

A Typical Day

I wake up at around 7:30, to Toby’s loud and demanding purr hovering above my head.  My long haired 13 pounder cat wants breakfast.  Or attention.   Both.  I pull myself out of bed and make a pot of tea.  Still in my pajama’s, I head over to the computer to check my email and my Etsy.   There’s a transaction, that’s nice, but just a tie bar.  And 7 convos.  About half of them are about custom orders I’m working on, where we’re still sorting out the details.  Others are requests: more photos for a ring, questions about a gemstone, or the availability of something similar to a listing.  A request for reserve that I turn down (many “reservists” don’t buy, but each “reservist” creates another request for a reserve).

More than half an hour has gone by and I’m still answering convos and relisting items.  I better hop into the shower or I won’t make the 10:30 subway to NY.  Then more listings, a quick photo session.  I check my To Do list and the Marilyn cosmetic bag where I keep what I have to take with me: a tie bar to engrave, some borrowed stones, earrings for setting, gems to be fitted for settings, and pre-assembled jewelry.  There’s a ring I soldered together, and a few things I started but then ran out of time.  I’ll let someone else finish the assembly.

After a quick breakfast, and one last convo, I head out.  I check my bag again.  If I forget anything - like my checkbook, or my list, or, God forbid, Marilyn - I have to run back.  I move the car to the other side for alternate parking, and dash to the subway.  I text the setter (“coming in today”), and the gemstone dealer, D.  

After a trip to the bank (mostly taking out money), and standing in line at the gold dealers, where they don’t have what I want in white gold, I go to the setter to pick up and drop off.  Something is soldered together wrong, I’m not happy but I swallow my anger.  I had added extra jump rings to the baggie (because sometimes they vanish) and now my dangly earrings have an extra hoop.  Ok, “let’s leave it,” I decide.  Not worth redoing because the item is stock and anyway, it would now have to be lazered because the stone is already set.  We discuss the new orders, I listen to a few jokes, pay for the orders received and head down the hall to the polisher with my pickups.

The setter could have just had it all polished of course, but him and the polisher hate each other.  Both are excellent, so I don’t want to switch.  Oil and vinegar, that’s what they’re like.  They try to mix, but each time they end up separating again.  I get free coffee at the polishers and drop off the jewelry that has to be rubber wheeled, sandblasted, rhodium plated. 

My next stop is the engraver, I give him the tie bar and instructions, then drop a ring with the guy who resizes for me.  He’s the best I know, never breaks a stone.  He’s bored though, so we chit chat, and I dash off to the casting service.  That place is slow, and there’s always a line, so I call ahead as I’m walking over and ask for my invoice to be prepared.  They put me on hold, and I stay on hold until I reach the building.  Oncein the elevator, I hang up.  Then I wait in line.  One order is missing (rose gold is cast only every two weeks), something else didn’t come out right.  It happens.  I inspect what I get, and realize that some items have to be prefinished (twig rings).  I head back to the polisher.

It’s 1:30 already and I don’t even know how that happened.  I need a break, I get more coffee and some hummus, and sit down at the gem dealer’s booth.  That’s my favorite place of course.  Someone comes by with a parcel of something, wants to sell.  “Nobody’s buying,” D. says.  Or: “Too much,” after having heard the price.  A jeweler pops by who broke a stone.  A really expensive tanzanite.  “Don’t have,” D. says, but feels bad.  He’ll call around.  I give back some stones I don’t need and pick up others for orders, for new listings, or just for fun.  Time really flies now, I look up and it’s 3:05.  I had better check on my orders. 

I pick up the tie bar, the ring, but the polisher’s not done though so I head back to D.’s booth.  Another gem dealer comes by with interesting emeralds.  But they should be double checked in the lab for treatment.  D. takes a sample out on memo, and I will take it with me the next time.  Another dealer shows up at D.’s booth, someone whom I owe money.  Oops.  I’m out of cash.  I need more anyway, so I run back to the bank.  I pick up with the setter, take stuff to the polisher.  Again.  And pay a bill.  Again.

It’s 4:30.  D. packs up.  “Done for the day.”  I’m pooped.  I inspect my orders, D. loupes the more difficult setting jobs to make sure nothing’s broken or cracked.  Then we head upstairs to the diamond cutter’s, where D.’s cousin is still busily shaving down a 25 pointer and J. is cursing out someone to blow off steam – he does that a lot but he doesn’t mean most of it.  D. has a beer, joins in the cursing.  I have some chocolate and a little Pinot Grigio out of a plastic cup, looking out of place but actually feeling at home.  J. shows me some diamonds he wants to sell to make money for the weekend.  Someone else with old jewelry shows up that will either be resold or melted.  I peruse but don’t find anything.  I’m out of cash anyway.

I catch the 6:00 subway back home.  I have to bend and polish the tie bar still, answer a convo and let someone know their order is finished.  Send out a paypal bill, print labels.  Eat dinner.  Pet Toby, who’s been waiting, and who keeps jumping up on my desk, blocking my view.  I think I need to go to bed.