An obverse design variation has been spotted by a Queensland half sovereign collector occuring in Jubilee Head half sovereigns of 1889-S and 1893-M. It's interesting that it occurs on a Melbourne and a Sydney mint issue as if they shared the obverse dies. We know that the two dates have always shared many similarities such as a incorrectly formed designed initials JEB, with the 1887 types and 1891 types having fully formed JEB (or none in the case of the common 1891-S type).
This new discovery, confirming the sharing of the dies between the branch mints occurs in approximately 20% of 1889 Sydney half sovereigns and 10% of 1893-M indicating a total count of about 100 for each type. The variation in design is detected by a slightly repositioned IEB and only 12 pearls in Queen Victoria's necklace. Normally there are 13 pearls in her necklace with two pearls visible in front of her neck where in the variety only 1 pearl is visible.
12 pearls
13 pearls
Enlarged 32x
Notice the doubling of the forward pearl in the right example - this is the common type. The left is the scarcer 12 pearl variety. As with any new discovery, valuations are yet to be matured and assuming you can find the already rare host coin, the variety shouldn't be priced any higher at this stage so it's certainly something worth looking out for.