"Sister Yu, I really have a use for these. Both the Black Crow Stone and Sharp Crystal Gold are extremely hard, and each has its own characteristics. Although the Sharp Crystal Gold doesn't possess element properties, it does repel all elements. I was thinking of using it as a weapon, which could more easily break through various elemental defenses. Take for example the Winged Tiger we encountered. The Winged Tiger has Wind Protective Energy, and my wind blade was utterly useless against it. I want to forge a weapon that can be enhanced by adding my wind blade to it, increasing the attack power. The Black Crow Stone serves a similar purpose, and since it's cheaper, I bought more of it. Sharp Crystal Gold is too expensive, so I'll just buy a little to try out for now," Tang San explained.