These bizarre calcites were found over 50 years ago in Santa Eulalia; this one came out of an old collection. They are very distinctive, most of them with one crystal having grown around and engulfed another, as in this case. The "inner" crystal was coated with dark hematite before the "outer" one encased it, which fortunately creates a wonderful contrast between the two crystals (this was common for this find). In very good condition! Superb example of twinning, as well.