Gem term question

[Tropicmaster]

What does it mean when a crystal is " terminated" ?

 

[zeolite]

It means it has regular, geometric, natural faces, just as the crystal grew. Usually looks slightly pointed, like a shallow pyramid. Means it is not irregular or broken.

 

[T L]

Here''s a terminated tourmaline crystal. I was told not to cut it since it had such nice "termination" which you can see to the right of the stone in this picture ----->

 

[zeolite]

When I said "natural faces", I should have added "natural end faces", which are the termination.

 

[Barrett]

heck..cut that sucker up TL..chop..chop

Here is a schrol tourmaline with a trignol termination

 

[Barrett]

A green tourmaline with a complex trignol termination

 

[Barrett]

a pink with a complex termination..

 

[Barrett]

An aquamarine/goshenite with a pinacoid termination..it''s where the crystal terminates to an end..the termination

 

[chrono]

Everyone has provided excellent examples.

 

[beaujolais]

Can you explain this one more:

trignol termination

To me, this would look like it broke off and was not a natural termination. How can I tell the difference? Thanks.

 

[T L]

Date: 8/12/2009 8:44:30 AM
Author: sonomacounty
Can you explain this one more:

trignol termination

To me, this would look like it broke off and was not a natural termination. How can I tell the difference? Thanks.

It doesn''t appear that way to me. My stone, which is an example of such termination, has completely finished it''s growth; therefore, it has such perfect and complete termination (at least that''s what I''ve been told by some mineral afficianados). I would think the flatter termination didn''t finish the growth process, but Amguy might have more to say on this. I''m not an expert.

 

[Barrett]

a termination will have what looks like natural facets..like all the examples above..it''s hard to see them in a 2-d picture but all the stones above save for the aqua/goshenite all have 3-d terminations..look for the natural facets..tourmaline can also grow a pinacoid termination like the beryl I posted but something like the green one and the one TL posted is a bi-trigonal pyramid..or laymas term "complex triginol termination"..it gets real complicated with certain crystals..like topaz..holy moly..you don''t even want to go there

 

[Tropicmaster]

Date: 8/11/2009 9:06:38 PM
Author: tourmaline_lover
Here''s a terminated tourmaline crystal. I was told not to cut it since it had such nice ''termination'' which you can see to the right of the stone in this picture ----->

Why would you not want to cut it? Is it worth a lot as shown? Thanks for all the answrs and examples- I now know what a termination is, although Amethystguy totaly lost me! lol

 

[T L]

Date: 8/12/2009 3:28:38 PM
Author: Tropicmaster

Date: 8/11/2009 9:06:38 PM
Author: tourmaline_lover
Here''s a terminated tourmaline crystal. I was told not to cut it since it had such nice ''termination'' which you can see to the right of the stone in this picture ----->

Why would you not want to cut it? Is it worth a lot as shown? Thanks for all the answrs and examples- I now know what a termination is, although Amethystguy totaly lost me! lol

I can''t find a cutter that will cut other people''s rough that I trust with the stone. Afghan tourmalines, which is what this stone is, have a propensity for cracking during the cutting process. I would love to have it cut though.

 

[beaujolais]

Thanks AmGuy. Now I get it.

Say, what would a broken crystal look like at the bottom?

 

[Barrett]

A broken crystal would look like a broken crystal at the bottom..not reall sure I understand the question...
Here is another thing you should know..we discussed terminated crystals..now there is also double terminated crystals..also called DT's and floaters..it's when a crystal forms in a pcoket or vug and forms without touching or growing on the walls like most crystals...a DT will have those "natural facets" on both ends with no broken section or contact point..DT's are decidedly much more rare than a non double terminatedf or regualar terminated crystal..here ids an example of a "herkimer diamond"(quartz)..herkimer is known for lots of DT's