January 24 Through February 4—TUCSON, ARIZONA: Annual show
Welcome to the GemologyOnline.com Forum
A non-profit Forum for the exchange of gemological ideas
It is currently Thu Mar 28, 2024 5:31 pm

All times are UTC - 4 hours




Post new topic Reply to topic  [ 25 posts ]  Go to page Previous  1, 2
Author Message
 Post subject:
PostPosted: Sat Mar 08, 2008 5:11 pm 
Offline
Active Member
User avatar

Joined: Sun Mar 02, 2008 7:32 pm
Posts: 75
Location: USA
brimsjewelry wrote:
An additional thought...

I can see the day when any stone NOT sold with a lab report or some kind of public certification MUST be considered synthetic or highly enhanced.

J-

I tell people that all the time who are buying Ruby and sapphire.
More than one local has gotten ticked off because I wouldn't take his word it was natural and unheated.
It was very clear that they had no clue about modern treatments and couldn't tell if they had too.


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Sat Mar 08, 2008 6:58 pm 
Offline
Platinum Member
User avatar

Joined: Tue Jan 02, 2007 8:20 pm
Posts: 2659
The shortest wave LEDs I have seen so far are 375nm , maybe 365.
If anyone has links to ones shorter than that I would be interested in looking.


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Sat Mar 08, 2008 7:52 pm 
Offline
Platinum Member
User avatar

Joined: Wed Apr 26, 2006 12:44 am
Posts: 2056
Location: San Francisco
why don't you use a deuturium lamp?? from wikipedia..

http://en.wikipedia.org/wiki/Image:Deuterium_lamp_1.png

The deuterium lamp emits radiation extending from 112 nm to 900 nm, although its continuous spectrum is only from 180 nm to 370 nm. It should be noted that the spectrum intensity does not actually decrease from 250nm to 200nm as shown in the spectrum plot above. The decrease in the plot is due to decreased efficiency at low wavelengths of the photo detector used to measure the lamp intensity. Deuterium Lamp's continuous spectrum is useful as both a reference in UV radiometric work and to generate a signal in various photometric devices.

_________________
Custom Gemstone Cutting and various other activities!


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Sat Mar 08, 2008 10:23 pm 
Offline
Active Member
User avatar

Joined: Sun Mar 02, 2008 7:32 pm
Posts: 75
Location: USA
G4Lab wrote:
The shortest wave LEDs I have seen so far are 375nm , maybe 365.
If anyone has links to ones shorter than that I would be interested in looking.


They aren't on the market because of eye safety concerns.
One of the problems with making them was getting them up too the safer areas.
EE times had a huge article on them a few years ago.
They were going too be classified as hazardous the same way higher power lasers are now.
Contacting one of the manufacturer's may get some place or may not.


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Sat Mar 08, 2008 10:30 pm 
Offline
Active Member
User avatar

Joined: Sun Mar 02, 2008 7:32 pm
Posts: 75
Location: USA
G4Lab wrote:
The shortest wave LEDs I have seen so far are 375nm , maybe 365.
If anyone has links to ones shorter than that I would be interested in looking.


linkage:
http://www.s-et.com/products.htm


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Sun Mar 09, 2008 1:22 am 
Offline
Gold Member
User avatar

Joined: Mon Apr 16, 2007 12:05 am
Posts: 1499
jleb wrote:
why don't you use a deuturium lamp??


Deuterium lamp intensity is spread out across the entire UV spectrum. Great if you want to collect UV transmission spectra. But not so great if you need a narrow band light source.

strmrdr wrote:
They aren't on the market because of eye safety concerns.


Well UV safety glasses cost about the same as chemical-resistant glasses, an order of magnitude or two cheaper than laser safety glasses. I think the UV glasses I recently purchased were less than $10 each. Each time I buy a different color laser, its another $500 investment for two or three pairs of safety glasses.

strmrdr wrote:


This is good news! They include a price list! I've found other sources for 250 nm LEDs, but they didn't have a price list, and I hated to ask. At slightly less than $300 each, these LEDs are about half the cost I had heard for them. I definitely have to purchase one for playing around with my UV-VIS spectrometer.


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Sun Mar 09, 2008 1:59 am 
Offline
Moderator

Joined: Sun Oct 16, 2005 12:42 pm
Posts: 2846
Location: Ho Chi Minh City, Vietnam
I've seen a couple of portable UV water purification systems online recently that are using LEDS at 254nm. I thought to myself "those would be great for the adventuring gemologist :lol: HERE and HERE.

THESE PEOPLE (whose BOGO lights are way too cool for any of you gadget guys) have also been testing a prototype using UV LEDS. I believe they are sourcing them from China. I might be able to find out for you, we know this guy.


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Mon Mar 10, 2008 6:53 am 
Offline
Platinum Member
User avatar

Joined: Tue Jan 02, 2007 8:20 pm
Posts: 2659
jleb d2 lamps are great for lab nerds like you and me. but they are a PIA
power supply wise and unless you buy them on fleabay they are expensive too. Same applies to their clunky non portable power supplies. (cept for the ocean optics and I think its hereaus that has a little cool one on a circuit board. But pricey.

Doesn't look like they are down to the 185-225 range with LEDs, which is what is needed to excite diamonds that are synthetic or HPHT treated.
I'll wait till they sort out all the safety issues and punch out a few zillion so
we can buy em for five bucks each.

It is a gas to watch all these developments.


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Tue Mar 11, 2008 10:19 pm 
Offline
Gold Member
User avatar

Joined: Mon Apr 16, 2007 12:05 am
Posts: 1499
Yep, looks like another year or two or three before LEDs break the 200 nm barrier. When that happens, they'll have moved outside my spectroscopic capabilities. But truly, it is really amazing to watch the progress of technology.

[old person voice] I remember when only infrared and red LEDs were available. Them and little neon tubes were state of the art, competing for calculator displays. [/old person voice]

Seriously, I was amazed the first time I could pay a couple bucks to get a blue LED. Some day, I may be saying that about deep UV.


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Wed Mar 12, 2008 1:11 am 
Offline
Platinum Member
User avatar

Joined: Tue Jan 02, 2007 8:20 pm
Posts: 2659
My brother in law is a Physicist and Engineer who quit his PhD to marry my sister and got an MBA and has been selling lasers for a LONG time. I remember [old person's voice] :D He told me you would be able to buy a four function calculator for $10. I thought he was completely pulling my freshman in college leg[/old person's voice] Six months later he was right.

F FWD When he was 11 I worked my 26 year old all summer to buy a 4x SCSI CD player that used a caddy. We still have it it still works. We paid $480 for it.


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 25 posts ]  Go to page Previous  1, 2

All times are UTC - 4 hours


Who is online

Users browsing this forum: No registered users and 5 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
Gemology Style ported to phpBB3 by Christian Bullock