---
type: Object
title: Saltglass
description: The islanders' dark volcanic glass, formed by Mount Sarn's old eruptions
  and gathered from the shore as pebbles.
tags:
- kelvarra
- volcano
- geology
- folklore
- the-institute
resource: raw/saltglass-and-the-shore.md
timestamp: '2026-07-16T15:09:31Z'
citadel_version: 0.3.0
---

# Saltglass

After a storm, islanders across the archipelago walk the wrack line before breakfast looking for saltglass.[^s1] Saltglass is their name for the dark natural glass of the islands: a volcanic glass, black as wet slate and glossier, poured out in sheets and seams by the old eruptions of [Mount Sarn](../misc/mount-sarn.md) long before anyone was here to name it.[^s2] The sea has been quarrying Sarn's old flows ever since, breaking the seams and rolling the shards for centuries in the boulder strands before delivering them up the beach as smooth, cold, black pebbles with a green-edged gleam unlike any other stone of the islands.[^s3]

## Where it is found

The best saltglass comes ashore on Sarn itself, on the storm beaches below the old flows, where the wrack line can glitter with it after an equinoctial gale. [Ilvess](../misc/port-ilvess.md) gets its share on the western strands at Corrie Ness, and [Little Moriny](../misc/little-moriny.md) a little; the outer skerries get the most of all but, in the boatmen's account, are the least worth the sail.[^s4] A good piece is judged the way pearls are judged, by depth and evenness — a pebble of true black with the green edge and no grey bloom changes hands in the fish market for more than the fish do.[^s5]

## Uses

Saltglass is Kelvarra's jewel, so far as the Republic goes in for jewels: it is cut and polished for ring stones and brooches, strung rough for luck, and set, by long custom, into the lintel of a new house — one pebble for each soul under the roof, so that reading a strange doorway is, in effect, taking a census. A bride wears a piece of it, a boat carries a piece in the keel, and the lamp room of every light in the archipelago keeps a pebble of saltglass on the sill, put there by keepers for as long as there have been keepers, for reasons no two of them give alike.[^s6]

## Properties and archaeology

Fresh-broken saltglass is sharp beyond any island metal; the middens on Sarn show blades and scrapers of it going back to the first settlement, and the shard beds below the old flows are, in effect, the Republic's oldest tool works.[^s7] The green edge collectors prize is a thin-section effect — the glass is not truly black but a deep bottle-dark, as a sliver held to the sun will show — and the grey bloom that ruins a pebble for the jeweller is the slow work of the salt itself, the sea taking back, molecule by molecule, what it spent centuries polishing.[^s8] The [Institute](../organizations/the-institute.md)'s geologists map the old flows and keep an affectionate eye on the shard beds, said to grade their own fieldwork by the pocketfuls they bring home; the essay's writer reports having seen their specimen drawers at the Institute's Corran Hill campus.[^s9]

## Supply

Whether the supply is endless, the islanders decline to wonder aloud. The sea has been generous for as long as the wrack line has been walked and the old flows are large, but Sarn — though its hot springs whisper otherwise — keeps its own counsel about making more; the prudent visitor buys a pebble in the fish market, hears the price, and concludes that the sea is not so generous as all that.[^s10]

## See also
- [Mount Sarn](../misc/mount-sarn.md)
- [The Institute](../organizations/the-institute.md)
- [Port Ilvess](../misc/port-ilvess.md)
- [Little Moriny](../misc/little-moriny.md)
- [The Saltglass Lens](the-saltglass-lens.md)

## Sources
[^s1]: [raw/saltglass-and-the-shore.md](../../raw/saltglass-and-the-shore.md), lines 5-8 — islanders walking the wrack line after a storm, looking for saltglass (ingested 2026-07-16)
[^s2]: [raw/saltglass-and-the-shore.md](../../raw/saltglass-and-the-shore.md), lines 10-12 — saltglass defined and its formation by Mount Sarn's old eruptions (ingested 2026-07-16)
[^s3]: [raw/saltglass-and-the-shore.md](../../raw/saltglass-and-the-shore.md), lines 13-18 — the sea quarrying and rolling the old flows into beach pebbles (ingested 2026-07-16)
[^s4]: [raw/saltglass-and-the-shore.md](../../raw/saltglass-and-the-shore.md), lines 20-23 — where the best saltglass comes ashore, by island (ingested 2026-07-16)
[^s5]: [raw/saltglass-and-the-shore.md](../../raw/saltglass-and-the-shore.md), lines 23-25 — grading a good piece and its price in the fish market (ingested 2026-07-16)
[^s6]: [raw/saltglass-and-the-shore.md](../../raw/saltglass-and-the-shore.md), lines 27-33 — cultural and folk uses of saltglass (ingested 2026-07-16)
[^s7]: [raw/saltglass-and-the-shore.md](../../raw/saltglass-and-the-shore.md), lines 35-38 — sharpness and the archaeological shard beds and middens on Sarn (ingested 2026-07-16)
[^s8]: [raw/saltglass-and-the-shore.md](../../raw/saltglass-and-the-shore.md), lines 38-41 — the green edge and grey bloom explained (ingested 2026-07-16)
[^s9]: [raw/saltglass-and-the-shore.md](../../raw/saltglass-and-the-shore.md), lines 41-44 — the Institute's geologists and their specimen drawers at Corran Hill (ingested 2026-07-16)
[^s10]: [raw/saltglass-and-the-shore.md](../../raw/saltglass-and-the-shore.md), lines 46-50 — folk uncertainty about whether the supply of saltglass is endless (ingested 2026-07-16)
