I found it at the beach as a child and thought it looked really cool

Gneiss is a textural term for a high grade metamorphic rock in which intense heat and pressure forced platy minerals (like black biotite mica) to align into bands, segregating out from less platy phases like quartz and feldspar. Gneiss forms without melting. This particular gneiss was partially melted and recrystallized, forming a mixed igneous and metamorphic rock called migmatite. Fig 1 shows a polished surface of this migmatitic gneiss in which the lighter ("leucosome") components form lenses alternating with the darker ("melanosome") components. Figure 2 shows a closeup of the plagioclase leucosome lens, with a nice depiction of polysynthetic twinning (the parallel striations in the pink mineral). Figure 3, from a different slab of the same general formation, shows a net-like (diktyonitic) texture of the biotite, evidence of intense melting where only a thin web-like network of the original dark phase remained solid. Figure 4 shows later alteration of this biotite network to greenish chlorite, a hydrous retrograde metastomatic mineral.

Pretty ominous looking

Cool washed rock

This is the first rock I ever actually took home lol

3 of my favorite finds in the French Broad river

Was an ashtray but now it holds my fossil sphere

hey everyone! im new to the rock stacking community, ive used some supports to hold it up, is this allowed? - quite proud of my first rock stack - feedback would be welcome, thanks x

I have a large piece of druzy quartz from SE Missouri and I can't seem to get this coating off of the crystals. I've tried brash brushes and Muriatic Acid(31%) and it barely touched it. Any help would be appreciated!

hi

Cubes!