5/8" Vitro Agate Co. Fancy Opal Conqueror Vintage Marble in Mint 9.9 condition. The last pic is backlit and reveals some iridescence.   

Did I get something wrong or leave something out?  It wouldn't be the first time so please contact me through eBay messages and let me know how I can improve this listing.  Thanks!

I combine shipping if you let me know that you are bidding on more than one listing. $5 flat fee for First Class 
Package anywhere in the contiguous lower 48 states for the first marble with any additional marbles purchased within 1 week of the first free of charge regardless of number. In the case of marble listings which include FREE SHIPPING ALL marbles purchased within a calendar week will be similarly shipped for free.  Please do not check out or otherwise pay for any listings which you would like combined during the 7 days as you add to your purchase.  Since eBay requires sellers to ship paid listings within two (2) business days from receiving payment checking out early may void the inclusion of additional marble purchases from this combined shipping offer.

Thank you for checking out this listing and be sure to see my other eBay listings!

I ship to the contiguous lower 48 United States only unless notified by eBay members in advance of bidding or purchasing. I would like to accommodate every eBay buyer whom purchases from anywhere and will gladly do so if contacted via eBay messages prior to any offers or bids made.

Purchases must be paid within 48 hours from the end of listings to avoid unpaid item notices unless other arrangements have been agreed to in advance or in the case of combined shipping selections in progress in which case buyers must check out within 48 hours from the end of the last listing.
Seller business hours:
Monday through Friday 9AM to 5PM
Saturday:  Closed
Sunday:  Closed
as well as every possible holiday which one may imagine including Feb 2 Ground Hog Day, Mar 3 If Pets Had Thumbs Day, Mar 5 Multiple Personality Day, May14 Dance Like A chicken Day, Sep 16 National Play Doh Day, Dec 5 Bathtub Party Day and 54 others more and less celebrated.

I use the marble grading system of the Marble Collectors Society of America which I have copied and pasted, ver batim, below. This system of grading marbles has been established and accepted by marble collectors, world-wide, as the universal system of grading marbles for decades and is used at marble shows, in person and online marble auctions and marble publications. Buyers beware of sellers paraphrasing the following grading system.
Mint: A marble that is in original condition. The surface is unmarked and undamaged. There may be some minor rubbing on the surface, however, the marble is the way it came from the factory.(9.0-10.0)*
Near Mint: A marble that has seen minor usage. There may be evidence of hit marks, usually tiny to small subsurface moons, pinprick chips, tiny to small flakes or tiny to small bruises. The damage does not detract from viewing the marble. If there is noticeable damage, then it is on only one side of the marble and the other side is Mint. (8.0-8.9)
Good: A marble that has seen usage. It will have numerous hit marks, subsurface moons, chips, flakes or bruises. The core can still be seen clearly, but the marble has obviously been used. If the damage is large or deep, then it is confined to one side and the other side is Mint to Near Mint. (7.0-7.9).
Collectible: A marble that has seen significant usage. Overall moons, chips, flakes, and bruises. The core is completely obscured in some spots. A Collectible marble has served its functional purpose and been well used. Still, it is a placeholder in a collection until a better example comes along. (0.0-6.9)
Note:  Any damage to the surface of a marble, no matter how slight, will affect its value. For a given amount of damage, the depreciation of value is much greater for machine-made marbles than for handmade marbles. Even a small chip will effectively reduce the value of a machine-made marble by more than half. Collectors tend to be more forgiving of damage to a handmade marble, perhaps because handmade marbles are more difficult to find. Some collectors use a 10x loupe to look for damage when grading marble. It is impossible to find any marble that does not have some mark on it under a 10x loupe. Every marble has rubbed against something. You will never find a handmade or machine made marble that can grade as a 10.