Difference in cast of clear crystal. grayish & clear

I have two clear leaded crystal, lidded round jars that are 6 inches high and about 6 inches across. They are cut glass in exactly the same pattern. They are about 5/16ths of an inch thick. My question is…one is a very clear and one has a slight greyish cast. What is the difference? Also, what are they? Most importantly, why is the difference in the cast of the clearness?

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Moved to General Questions.

Colibri
General Questions Moderator

Possibly the slightly greyish one has more than the optimal amount of lead. Or I suppose it could be microscopic air bubbles making the glass slightly cloudy.