NR8M3: Nice and interesting miniature. Complex Calcite crystal with dominant scalenohedral faces. Inside one can see a very acute scalenohedron phantom. On a small matrix with Dolomite and Sphalerite.
The sample has been noted and photographed in the article 'The Áliva Mining District' of the ‘Mineralogical Record‘ magazine on page 391 in the volume 52, number 4, July-August 2021
Áliva Mine (Las Mánforas Mine), Áliva mining area, Camaleño, Comarca Liébana, Cantabria  Spain

Specimen size: 3.3 × 2.5 × 2.1 cm = 1.30” × 0.98” × 0.83”

Main crystal size: 3 × 2 cm = 1.18” × 0.79”