In its normal state (annealed), tantalum has a Vickers hardness of around 125HV, which is more than four times that of gold and about three times that of platinum in the same state. Compared to the ubiquitous gold and platinum rings, tantalum rings have a much higher hardness.
Tantalum is not only resistant to corrosion by aqua regia under pressure at temperatures up to at least 150°C but also to corrosion by peroxymonosulfuric acid. Even when continuously heated in pressurized peroxide at 125°C for several days, tantalum shows no signs of corrosion.
With proper protection, the mirror surface of the ring can be maintained for a long time. However, if not protected and subjected to frequent abrasion, any metal ring, no matter how hard, will get scratched after a day's wear.
The No.73 Plus tantalum ring can be customized with engraving. For international shipping, non-engraved rings will arrive in about 14 days. If engraving is required, an additional 5-7 days are needed for engraving. Whether customized or not, the inner circle of the ring will have material and purity markings.