Bournonite (“cogwheel”) on matrix blue-green ambrosia beetle (Platypododae)

ambrosia beetle (Platypododae)

It's not completely unstable like decomposing Limonite and it provides a much more appealing contrast than ordinary Pyrite

This material is rarely seen in today's market and this particular specimen is at least 35 years old

which is not often found in well-crystallized display specimens

silvery bladed crystal of metallic Bournonite on iron-stained micro-crystallized Quartz

Bournonite (“cogwheel”) on matrix blue-green ambrosia beetle (Platypododae)Finding a fine quality "cogwheel" such as this on matrix from Machacamarca is not common, and the photos honestly do not do this piece justice as it is much more eye catching in person. This piece features a few attractive "cogwheel" twinned crystal groups of Bournonite with superb luster sitting atop a matrix of micro Pyrite, Quartz and Sphalerite. The "cogwheels" feature dozens of discreet, striated "cogs" that form the edge of the fairly thick