Something for the petrologists: an unusually coarse-grained sample of the rare magmatic cumulate rock type allivalite, a variety of troctolite consisting almost entirely of very pure anorthite and forsterite, named after Allival Hill on the island of Rhum, Scotland. This particularly fine 7.5cm specimen of allivalite shows iridescent forsterite and partly gemmy anorthite, from Miyake island, which is about 200 km out in the Pacific Ocean from Tokyo, Japan.
Abundant thin pink sheets of native copper included in a 1cm unusually pure anorthite (almost-end-member, An97), embedded in a 4cm lump of lava from Miyake island, Tokyo, Japan. Anorthite from here is perhaps the world's purest, and a Dana classic known since the late 19th century, but very few of them have naked eye visible copper inclusions.
Red Opal, 4cm, from Satsuma Iwojima island, deposited from HF-rich gases around fumarole vents. The red color is from included hematite, presumably derived by hydrolysis of Fe chloride vapor. Most of the opal on this volcano is white, and red ones are rare.
First find ever of analytically confirmed turquoise from Bolivia! 6.5cm. But it's only a thin crust (so far), so no jewellery :((
Fossils are not usually found in volcanic rocks, for obvious reasons, but there are exceptions, like this sweet little Devonian brachiopod in a 1cm whitish sandstone xenolith dragged up to the surface by a Holocene (late stone age) scoria cone eruption in the Eifel hills, Germany.
Smashed open a boulder of cinnabar from Almaden and this native mercury just sweated out on the fresh surface.
Rainbow inside Herkimer quartz crystal.
In Kyoto City, just a few hundred meters from some of the famous "tourist trap" temples and the beautiful cherry blossom trees along the Philosophers' Walk, there is a much less well known locality for "cherry blossom stones", more crudely shaped, as you can see.
Native copper "chains" included in almost end-member anorthite (An 96<97). Miyakejima, Tokyo.