FMF - Friends of Minerals Forum, discussion and message board

[daviddillman]

My daughter found these two hematite included quartz points at a pegmatite in Mason County, Texas. I found the the "concave sections" of the points prettying interesting and several other of the points she found had similar features. After some trial and error I realized these two points fit very snuggly together such that they look like a single specimen. The only sign of breakage is towards the bottom. What is the technical term for these type of crystal growth? How common is this type of thing?

[daviddillman]

some more pictures in case the initial ones are not enough

[mayer813]

I believe it is called a twinned crystal. If they share a crystal lattice they are called contact twins which I think these do share a lattice.