im not a complete dumbass but....

[stewie]

I am sitting here drooling over my SS Daytona, and I have learned a ton from this site. SEL, clasps, hands, faces, etc.. One thing I would like to learn more about is the crystal. How do they make it? How do they make it so scratch resistant? how thick is the crystal? I think I read somewhere that they "grow" them in tubes... How is that done? Am I asking enough questions?

[JJ Irani]

Originally Posted by stewie

I am sitting here drooling over my SS Daytona, and I have learned a ton from this site. SEL, clasps, hands, faces, etc.. One thing I would like to learn more about is the crystal. How do they make it? How do they make it so scratch resistant? how thick is the crystal? I think I read somewhere that they "grow" them in tubes... How is that done? Am I asking enough questions?

Hi Stewie,

Just do a google search for "sapphire crystal" and I think you'll find most of your answers there.

Cheers - JJ

[stewie]

Originally Posted by JJ Irani

Hi Stewie,

Just do a google search for "sapphire crystal" and I think you'll find most of your answers there.

Cheers - JJ

JJ, whats a "google"?

[SPACE-DWELLER]

Only a diamond can scratch a sapphire crystal!.......in principle, that is!

Now, a sapphire has a hardness coefficient of 9 on the Moh's scala. Diamond is the hardest material on Earth (10 Moh). But nevertheless, sapphire crystals are only scratch resistant to an extend. They sure are synthetic/lap grown, but I would also like to know how exactly they're manufactured.

I guess I'll have to "use the search button"

[Timber Loftis]

http://en.wikipedia.org/wiki/Sapphire_crystal

Scratch resistant, but not scratch proof. Got a miniscule nick in my watch by hitting it on a sharp metal doorknob edge. The stuff can't be buffed out, but replacing it isn't that expensive. On my Exp.II the price to replace it was about $130. I figure I'll wait for a few more dings and nicks first, but it sounds pretty reasonable.

[Silvio]

I’m not an expert but this is what I know: Sapphire crystal is made by crystallizing aluminum oxide at high temperature. Unlike natural sapphire and ruby, sapphire crystal doesn’t have iron, titanium and chromium.

[Mike734]

Originally Posted by SPACE-DWELLER

Only a diamond can scratch a sapphire crystal!.......in principle, that is!

Can't they make crystals out of diamond? That would be cool.

[tnt]

Originally Posted by Mike734

Can't they make crystals out of diamond? That would be cool.

may be in the near future, perhaps? and if you don't mind for that deep hole in the pocket goes along.

[marshallr47]

Modern Rolex watches have the synthetic sapphire crystals(home grown in tubes). There are certain watch companies that have actual sapphire crystals like Patek and other very high end watches. I believe they are the same as far as scratch resistance.

[Andad]

From the web.


http://www.rayotek.com/techincal_inf...s_sapphire.htm

SAPPHIRE


Sapphire is a single crystal - Aluminum Oxide (Al2O3) - which is colorless and optically clear. Synthetic sapphire is grown in boules (bulk pieces) no larger than 300mm in diameter. It can also be grown into shapes such as sheets, ribbons, domes and tubes with very smooth surface qualities, high purity and optical translucence. When used "as grown" there is very little need for grinding and polishing.

WHY SAPPHIRE?


• Mechanically second only to diamond. One of the hardest and most scratch resistant materials
available. The high modulus of elasticity and high tensile strength make it extremely wear,
abrasion and impact resistant.
• Colorless optical characteristics are superior to any standard glass, with up to a 98.5%
transmission and a transmission window from 190 nanometers in the UV to 5 microns in the IR.
• No solarization in high-radiation systems.
• High dielectric constant and low loss tangent makes it a great electrical insulator and low
loss long wavelength window.
• Thermally very stable. Does not lose any of its mechanical and optical qualities from cryogenic
to over 2000C.
• Thermal conductivity greater than other optical materials and most dielectrics.
• No surface damage and devitrification due to extreme thermal cycling
• Does not sag or slump at very elevated temperatures.
• Highly corrosion resistant. More resistant to corrosive chemicals than most standard hard
materials available.


WHY NOT SAPPHIRE?


• Cost of material. Sapphire often costs more than other refractory materials. But not always!
Quantity and geometry play a major role in the cost of the final product, especially with smaller
products where the labor is the primary cost.
• Cannot be bent, molded, drawn or melt-fused like glasses and metals. Sapphire can only be
ground and mechanically polished.
• Size limitations. The maximum size of a sapphire product cannot exceed the largest boule
that can be grown. Therefore, maximum part size cannot exceed 300mm for two of the dimensions.
• Larger pieces can be thermally shocked and broken if not heated uniformly.


Also some interesting info on ceramics.

[Arturo]

Whew...thanks for that amazing bit of information Eddie....I respect the stuff a whole lot more after reading that.