Purple Zealio switches are clones of Cherry MX switches, manufactured by Gateron for ZealPC (which is the answer to your other question). They use lighter springs compared to genuine Cherry MX Clear; the idea originated from "ergo clear" modification many years ago. Cherry Corp. required very high MOQ, when they were asked to mass produce such switch configuration, thus it didn't work out back then.
In terms of technical differences (besides stock springs), gaterons (including zealios) have had significant quality/consistency problems, but they're regarded as smoother (zeolios come lubed out of the box too AFAIK) and usually have clear covers/housings.