Where can I buy a lens blank?

For experimentation purposes, I would like to buy a plain, any
material, coating of no consequence, lens blank, at least 30mm
diameter, with either plus or minus 0.25 diopter (FL= 4 meters
divergent or convergent). Where can I find this, and what would be an
estimate of cost?

Thanks!

You might try this company:

http://www.edmundoptics.com/



On Sep 21, 8:06*am, GeorgeB <nos...@att.net> wrote:
> For experimentation purposes, I would like to buy a plain, any
> material, coating of no consequence, lens blank, at least 30mm
> diameter, with either plus or minus 0.25 diopter (FL= 4 meters
> divergent or convergent). *Where can I find this, and what would be an
> estimate of cost?
>
> Thanks!

On Sep 21, 8:06*am, GeorgeB <nos...@att.net> wrote:
> For experimentation purposes, I would like to buy a plain, any
> material, coating of no consequence, lens blank, at least 30mm
> diameter, with either plus or minus 0.25 diopter (FL= 4 meters
> divergent or convergent). *Where can I find this, and what would be an
> estimate of cost?
>
> Thanks!

Any optical that sells glasses can order a blank for you. Cost would
be under $20, likely under $10.