What kind of light is it?

[jewlie beads]

I've heard of some people using a light to find hidden cracks in their lampwork beads. Can some one please tell me what kind of light this is? Can you buy it anywere like at Lowes or something Or is it a special light that is made for this purpose?

[suzanne]

I believe it's called a spectrometer, you could try Frantzartglass

[RSimmons]

You can use a Polariscope on clear glass to find stress lines. Doesn't work with opaques.

Robert

[Dale M.]

Ditto on polariscope....

Dale