If you are using the white sand in a pebbledash finish then it is fine. Personally though I find it inevitably looks a little tired looking after a few years. As a sand for a smooth or napped finish then, again, personally I would not advise it. It is a sand that when gauged is not eay to work with as it has a fatty consistancy and is a devil to float, its fine for dashing because it is laid on and that is it, the fatty consistancy is perfect for receiving a dash but not for a float finish. The one and only time I have seen white sand used was on boundary walls and I was there to help lay it on but left as th polish plasteres finished it off.....It was a poor finish and dried inconsistantly. This could have been an indication of the quality of the plasterers as opposed to the materials however. If you are using plasterers that are familiar with the method and materials then it may well not be a problem. Again if it is for a dash ensure that the spreads ensure that the piecings, which are the joints between each lift of plastering at each scaffolding hweght are straight, nothing looks worse in a dash finish than poor piecings that stand out a mile and spoil what is otherwise a nice finish.