Exquisite filigrees of beautifully burnished, herringbone-patterned, spinel-twinned silver crystals very richly cover the greenstone matrix plate on this outstanding specimen from the famous El Bonanza Mine at Port Radium, Northwest Territories, Canada. I am told these were found over 50 years ago, and I have seldom seen them available. The very dense spinel-twins are in a 1.3 cm thick vein of solid silver.