Light of Other Days, by Bob Shaw

One other for today. Light of Other Days is more of an early story in classic mode, in that it stands alone--never was going to be a novel, not part of a series. An interestingly impossibly scientific premise is turned to the end of a good human tale. These are the stories that can stand up over time. This one seems a little familiar to me, I think I have read it before. Glass that can trap light for years at a time stores up scenes of beauty, and also of tragedy. Too hard to explain much without giving it away, just read it.