The coin is a 1961 Australian penny, Perth Mint. The coin is about the size of a US half dollar. I believe the heavy lines in the field are a mint error. What caused them? A 2 photo composite of the obverse Composite of the reverse.
The large lines in the field? Do you think that they are metal flow lines due to die wear? Polishing lines? I recently bought an AU/UNC '61 penny with the same large lines in the field. The seller said that his coin was struck with oily dies. I'm having a hard time imagining how oily dies caused those striations in the field. Here are his photos (I haven't received the coin yet).
That's not what happens. Grease used to wipe the Die gets into the incused parts of the die. After many strikes it can become compacted which would fill the areas. The striations is just the wear on the face of the die after thousands of strikes.
Even uncirculated coins can show the effects of die deterioration without dropping the grade to AU/EF. The fact that the seller claimed that it was struck with oily dies only proves that he was stupid and you should be careful about buying coins from unknown sellers. Chris
Not necessarily stupid, but definitely unknowledgeable. You can't fix stupid, but ignorance can be corrected through education.
Thank you all for your replies. The striations looked like flow lines to me too. I just wanted to test the waters to see if anyone would agree with oily die. FYI, I bought one other Australian copper with the heavy flow lines. This one a ’61 halfpenny. It was listed as an UNC. I haven’t received this one yet. Would you consider this one an error? There is a large transition in the coin surface around Elizabeth's cheek.
