1838 half sovereign and rather nice. I got this coin probably 15 years ago and appears fairly nice with toning. This came from an old Goldberg auction in is an old green PCGS holder. I thought it may have been conservatively graded but note it has toned a bit in the holder. I have some other thoughts but will first show it: comments, GTG?
64? The reverse looks as though it might be slightly prooflike. Lovely. I’ve not owned any Shield type sovereigns or half-sovs. Only St. Georges.
Well, here is a thought of mine (or maybe fear?): could this have been puttied? I haven't really seen gold to tone in the holder otherwise and the obverse surfaces just look "different". I will post some more under natural light tomorrow. There appear to be superficial swipes (not into the metal) at the base of of the bust and in the field to the left of Vicky on the obverse & even above the bust and to the right. When the coin is rotated the metal looks good; but I am tempted to have it conserved - what do y'all think? Anyway, the coins surfaces and esp. on the reverse as has been pointed out are quite nice. PCGS gave it a 63 but will note that I have a number of earlier Vicky half sovs and not always sure about the grading on these - i.e. the TPGs can be IMHO way off and to the tune of 1-2 numerical grades high or low.
Do you have a photo of the coin before the toning? Gold is not a reactive metal, and it takes a long time for a gold coin to acquire color, caused by the alloy mixed with the gold, usually copper. The only other cause might be instability with the plastic used for the slab? I don't think this the case; hard plastic, unlike PVC plastic, should have any leaching chemicals. As for putty or some other material applied to mask damage or a flaw, I don't think that is the case. The surface just looks as if a thin deposit of some substance over time darkened. I had a broad 1 1/2 thaler from the 17'th century that had a hole repaired with wax. The wax was colored to match the silver tone of the coin. This was a very old fashion way of repairing holes.
These don’t help much as the coin has to be seen in hand. I don’t have pics from earlier and when looked up at PCGS they are no longer there:
