- NGC 869 (Wikipedia)
NGC 869 (also known as h Persei) is an open cluster located 7460 light years away in the constellation of Perseus. The cluster is about 14 million years old. It is the westernmost of the Double Cluster with NGC 884.
- Geode (Wikipedia)
A geode (/ˈdʒiː.oʊd/; from Ancient Greek γεώδης (geṓdēs) ’earthlike’) is a geological secondary formation within sedimentary and volcanic rocks. Geodes are hollow, vaguely spherical rocks, in which masses of mineral matter (which may include crystals) are secluded. The crystals are formed by the filling of vesicles in volcanic and subvolcanic rocks by minerals deposited from hydrothermal fluids; or by the dissolution of syn-genetic concretions and partial filling by the same or other minerals precipitated from water, groundwater, or hydrothermal fluids.