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Tanzanite or sapphire?

fzpanda

Rough_Rock
Joined
Aug 22, 2011
Messages
59
My mother's birthday is approaching, and I am struggling to decide between a 25CT tanzanite and a 6CT sapphire as her birthday present. Both stones are beautiful. But my experiences with tanzanite are quite limited, so I have the following questions:

(1) Hardness of tanzanite is only around 6.5. Is it too soft for everyday use?
(2) Price of tanzanite fluctuates dramatically over the past few years, is it likely that the price for the best quality tanzanite will take a substantial dip in the future?
(3)My jeweler told me that tanzanites that display reddish-purple flashes command a premium and is considered the best quality, is this true?

Any inputs are highly appreciated.
 

Roger Dery

Shiny_Rock
Joined
Mar 25, 2009
Messages
297
fzpanda,
I am struggling to decide between a 25CT tanzanite and a 6CT sapphire
Both beautiful gemstones, and what a fortunate mother!

(1) Hardness of tanzanite is only around 6.5. Is it too soft for everyday use?
Hardness is only one factor to consider when choosing a gemstone for wearing on the hand or as a bracelet. One needs to look at overall durability. Sapphire (and Ruby) are very durable and can normally withstand every-day wear. Tanzanite on the other hand will not hold up well for daily use (on the hand). Since I started in the trade it is the one gemstone we've had to repair most frequently.

That being said, if you were to mount a 25ct Tanzanite into a neck-piece, it would stand little chance of acquiring damage.

(2) Price of tanzanite fluctuates dramatically over the past few years, is it likely that the price for the best quality tanzanite will take a substantial dip in the future?
Tanzanite peaked in price in the late 80's and again in the late 90's. Rough prices hit their most recent low in 2009. I just returned from Tanzania on Friday and while there spent some time reviewing rough and cut goods. In a same size comparison, just a few days ago, prices were up 45% from summer 2010. With the increased demand coming from China, India and other emerging markets, I suspect prices will move up gradually. In addition, the one Tanzanite miner we met with, is currently at just over 800ft in depth. He has a crew of 15 workers. Unless there is further erosion in financial markets, my guess is prices will still rise.

(3)My jeweler told me that tanzanites that display reddish-purple flashes command a premium and is considered the best quality, is this true?
I believe if you polled gem lovers that are consumers, you may find their opinions differ from those of your jeweler. As a gem cutter and gem lover, I prefer a rich blue with a secondary purple hue. But that may just be me.

I hope you found this helpful.
 

fzpanda

Rough_Rock
Joined
Aug 22, 2011
Messages
59
Thanks Roger for the very detailed response. Truly appreciated. The purple-red flashes I mentioned in my post can't be seen all the time. They can only be seen when you rotate the stone under the light on some facets. The main hue of the tanzanite I have my eyes on is still VB. The flashes kind of resemble light reflection. Is this common to find in tanzanites?
 

Roger Dery

Shiny_Rock
Joined
Mar 25, 2009
Messages
297
fzpanda|1315761244|3015094 said:
Thanks Roger for the very detailed response. Truly appreciated. The purple-red flashes I mentioned in my post can't be seen all the time. They can only be seen when you rotate the stone under the light on some facets. The main hue of the tanzanite I have my eyes on is still VB. The flashes kind of resemble light reflection. Is this common to find in tanzanites?
fzpanda,
We have two characteristics at play here.

1 ~ Pleochroism and/or Dichroism
In non-technical terms, this is where you have more than one color present due to 2 or 3 different light paths traveling through the stone. This effect is prominent in gems like Iolite, Tourmaline and Tanzanite and are usually easily visible. In Tanzanite specifically, it starts out with 3 paths (pleochroic). But after heat treatment to convert it to violet-blue to blue, it then has 2 paths (dichroic). The pleochroic effect is visible when rotating the stone through the various viewing planes. At this point, one direction should have prominent blue, and another plane should have more pronounced purple. But this can vary so it may be helpful to not get caught up in its perfection.

2 ~ Metamerism
This optical effect is directly related to the color temperature of the light source. Therefore, it would be uncharacteristic for *any* gemstone to be the same color in every light source. This is a physical effect that is seldom understood, and often misconstrued by people in the trade as well as consumers. Attempts to reduce the metameric effect is often noted in the clothing, fashion and paint industries as they are acutely affected by minor changes in color temperature.

I hope you find this helpful.
 

fzpanda

Rough_Rock
Joined
Aug 22, 2011
Messages
59
Roger Dery|1315769632|3015169 said:
fzpanda|1315761244|3015094 said:
Thanks Roger for the very detailed response. Truly appreciated. The purple-red flashes I mentioned in my post can't be seen all the time. They can only be seen when you rotate the stone under the light on some facets. The main hue of the tanzanite I have my eyes on is still VB. The flashes kind of resemble light reflection. Is this common to find in tanzanites?
fzpanda,
We have two characteristics at play here.

1 ~ Pleochroism and/or Dichroism
In non-technical terms, this is where you have more than one color present due to 2 or 3 different light paths traveling through the stone. This effect is prominent in gems like Iolite, Tourmaline and Tanzanite and are usually easily visible. In Tanzanite specifically, it starts out with 3 paths (pleochroic). But after heat treatment to convert it to violet-blue to blue, it then has 2 paths (dichroic). The pleochroic effect is visible when rotating the stone through the various viewing planes. At this point, one direction should have prominent blue, and another plane should have more pronounced purple. But this can vary so it may be helpful to not get caught up in its perfection.

2 ~ Metamerism
This optical effect is directly related to the color temperature of the light source. Therefore, it would be uncharacteristic for *any* gemstone to be the same color in every light source. This is a physical effect that is seldom understood, and often misconstrued by people in the trade as well as consumers. Attempts to reduce the metameric effect is often noted in the clothing, fashion and paint industries as they are acutely affected by minor changes in color temperature.

I hope you find this helpful.

Thanks. That's indeed quite helpful.
 

LD

Ideal_Rock
Premium
Joined
Jun 29, 2008
Messages
9,714
fzpanda|1315756351|3015039 said:
My mother's birthday is approaching, and I am struggling to decide between a 25CT tanzanite and a 6CT sapphire as her birthday present. Both stones are beautiful. But my experiences with tanzanite are quite limited, so I have the following questions:

(1) Hardness of tanzanite is only around 6.5. Is it too soft for everyday use?
(2) Price of tanzanite fluctuates dramatically over the past few years, is it likely that the price for the best quality tanzanite will take a substantial dip in the future?
(3)My jeweler told me that tanzanites that display reddish-purple flashes command a premium and is considered the best quality, is this true?

Any inputs are highly appreciated.

25ct of Tanzanite is HUGE! If you're contemplating putting it in a ring then no, it's not suitable for everyday use but as Roger has said, a pendant would be fine. I've got an 18ct Tanzanite that's wayyyyyyy too big for a ring! If you want to see photos, let me know and I'll post them up.

I slightly disagree with Roger in terms of pricing and I think it depends on where you are in the world. In the UK 5-8 years ago, you could get mounted Tanzanites for around $300-$400 per carat (for top quality material). The price is still the same. The problem is that Tanzanite has flooded the market and whilst most people bought years ago believing the hype of "this is rare and will run out soon", it hasn't!!!! If anything Tanzanite took a dip in price several years ago and shows no sign of recovering at the moment. With the economy as it is, increasing in value would be surprising.

Like Roger, I prefer an intense blue with a purple secondary and this is certainly what collectors look for. Most Tanzanite will display red/pink flashes but it depends on the lighting conditions and cut of the stone. I don't believe that this phenomenan is isolated to just top quality either so I wouldn't factor that in when buying. The best Tanzanite looks like a regal blue/purple and is incredibly rich and warm looking. For some really nice pieces have a look at www.lapigems.com

Hope that helps.


EDIT: Just found a photo of one of mine that shows pink flashes. Although a great cut, this is NOT top quality Tanzanite.

Tanzanite Snowflake Pendant_ trim for ps.JPG
 

Michael_E

Brilliant_Rock
Trade
Joined
Nov 19, 2003
Messages
1,290
Roger Dery|1315760290|3015083 said:
That being said, if you were to mount a 25ct Tanzanite into a neck-piece, it would stand little chance of acquiring damage.
This is true, unless you're like my ex-wife. She had a hilarious habit of forgetting when she was wearing a necklace and would periodically dunk the necklace that she was wearing in bowls of soup when we'd go out to dinner. :lickout: :lol: It was one of those things that I really looked forward to, though I'm sure that she wasn't as amused as I was. If you're a "soup dunker" you may want to get a stone that is a bit less heat sensitive than tanzanite.
 

fzpanda

Rough_Rock
Joined
Aug 22, 2011
Messages
59
Thank LovingDiamonds. That tanzanite of yours is still quite beautiful! I have decided to make my tanzanite into a pendant. Thank you all very much.
 

fzpanda

Rough_Rock
Joined
Aug 22, 2011
Messages
59
And in terms of price, I was asked to pay about 500 a carat for supposedly DBlock material. Is this a reasonable price? I took a look at Lapisgem website, and it appears they charge about 700-800 per carat for their tanzanites...
 

marcy

Super_Ideal_Rock
Premium
Joined
Feb 27, 2007
Messages
24,125
You will love the pendant. That is pretty reasonable for D block material. I love the color or tanzanite.
 

LD

Ideal_Rock
Premium
Joined
Jun 29, 2008
Messages
9,714
$500 is a good price (and right) for high quality material. However ignore "D Block". Whilst it was fair to say that this area of the mine did produce good material, it also produced bad! It's been used as a marketing/selling term and in all reality unless the vendor bought direct from the mine (impossible unless they are one of the 7 or 8 sight holders) it's questionable they'd know whether it's D Block material or not. Ignore the selling/hype and buy with your eyes and what you like!
 

chrono

Super_Ideal_Rock
Premium
Joined
Apr 22, 2004
Messages
37,517
Look at the stone and buy the look, not the name. If I received a penny every time I hear the term D Block as it relates to tanzanite...you get the idea. :bigsmile: Based on the actual colour, pricing per carat will vary.
 
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