The "Hourglass" belongs to Perth Mint's Shapes series, which began leaning heavily into rimless, curved, and sculptural formats after the secondary collector market demonstrated consistent premiums for geometrically unusual blanks. Perth developed its own proprietary pressing techniques to achieve the meniscus profile without cracking the high-purity .9999 silver — a purity level that makes blanks more ductile but also more prone to flow lines under unconventional die geometry.
The "Hourglass" belongs to Perth Mint's Shapes series, which began leaning heavily into rimless, curved, and sculptural formats after the secondary collector market demonstrated consistent premiums for geometrically unusual blanks. Perth developed its own proprietary pressing techniques to achieve the meniscus profile without cracking the high-purity .9999 silver — a purity level that makes blanks more ductile but also more prone to flow lines under unconventional die geometry.