- Bournonite, Quartz
- Thumbnail, 2.5 x 1.4 x 1.2 cm
- Yaogangxian Mine, Yizhang Co., Chenzhou Prefecture, Hunan Province, China
Fine, sharp bournonite crystals have always been very rare, until the finds at Yaogangxian starting turning up. Here is a superb thumbnail, with a spray of quartz crystals attractively slanting across it.