Smoky quartz point with hyalite

Locale: Erongo Mountain, Namibia

Point length: 3"

Approx weight: 109g

Smoky quartz from the Erongo region is typically a quite dark brown-black color, with lower clarity due to natural inclusions, and a flat surface luster caused by etching. It grows sculptural angular points with nice striations like this triangular piece. Paired with hyalite, the smoky quartz takes on a witchy appearance. I would dub these points "witch's fingers" but there is already a variety of quartz called that so I use "witch's manicure" instead.

This point looks quite light colored from some angles, and near-black from others. The smoky quartz has ghostly dark tint around the areas coated in hyalite, and small dark spots nearby. Smoky quartz gets its dark coloration from trace elements that tint dark when the quartz is exposed to natural radiation. Don’t worry, smoky quartz can't expose you to radiation—even if the hyalite turns "radioactive" green under UV light.

Hyalite is a form of opal, which in turn is part of the broader quartz family. Related minerals commonly grow together because they have similar requirements for growth: in this case, the availability of silica that is the basis for the quartz family. Growing conditions that initially produced quartz changed, and a later generation of growth deposited the less common hyalite on the specimen.

Hyalite displays botryoidal growth (bunches of “grape-like” round crystals) with a glossy high luster like a layer of bubbles. I think it looks like mermaid caviar! Hyalite can appear fluid with formations that look like the splash from a drip frozen in place, or as if the edge has been peeled up away from the quartz like a tutu.

This material often has a mish-mash of broken minerals entrapped and attached to the quartz surface by the hyalite, as found at the base of this piece. The opaque white mineral is albite and the black is schorl (black tourmaline), with iron causing the orange coloration. Near it is a cluster of well-formed smaller smoky quartz crystals; when exposed to UV light this area of the quartz glows as if more hyalite is trapped inside the point, which is unusual given that it typically forms on the quartz surface (I didn't do the best job of photographing it!).

UV reactivity Hyalite is so strongly UV reactive that you can see it in sunlight. Under indoor lighting it is pale yellow to golden in color, but turns visibly greenish yellow when exposed to the UV in sunlight. 395nm UV fluoresces a strong green, with an icy blue undertone. Best viewed in darker conditions. 365nm UV fluoresces a strong yellowish-green color, generally visible even in bright lighting. No phosphorescence detected.