Basalt Vellum

Basalt Vellum is the collective designation for sheets of basaltic stone cut and ground to a thickness of 0.8 to 1.2 mm for the purpose of receiving permanent inscription. It is neither vellum nor basalt in any ordinary sense — the name is a Concordance artifact, retained because no substitute has survived committee — but the material's properties are well documented: it is non-porous, dimensionally stable at temperatures between 4 and 61 degrees, and takes a chisel-cut without spalling. A sheet of Basalt Vellum is quarried, ground, and inscribed within the Tower; at no point does it behave as paper.

Quarrying and Preparation

Stock is drawn principally from the Lower Quarries, where Attenuated Basalt is distinguished from veined stock by the absence of visible veining or crystalline inclusion. Vein-free basalt is required for Basalt Vellum, as any dendritic calcite intrusion will propagate a fissure under a struck chisel. The Basalt of the Seventy Seventh Spiral supplies a coarser, darker grade reserved for working drafts and rejects; it is not accepted at the Central Vellum Repository.

Sheets are ground between the fourth and eleventh of each month by the Grinding Clerks of the Ninth Gallery, who work in a cold-water slurry to keep dust from settling on the Vellum Stacks above. A sheet that measures outside tolerance by more than 3 mm is not returned to the quarry; it is passed to the Sub-Basalt Floors for paving, where its flatness is still wanted.

Inscription

Basalt Vellum admits three methods of record: struck inscription, incised inscription, and — where the sheet is to remain flexible — the process used on Vellum of Permanence stock, which is not Basalt Vellum and should not be confused with it. Binding of Basalt Vellum is impossible without cutting; sheets are therefore drilled and laced, or set in frames. The Master Copy of Clause 19 is a single sheet of the material measuring 112 cm by 74 cm, and its survival intact is cited by the Recording Practices Concordance as the standard against which all archival binding is judged.

Ink and Interface

Conventional inks do not adhere to Basalt Vellum. Ink is confined to the incised channel, and the material is finished, when finish is required, with Basalt-Weave, a non-reflective substrate developed by the Archivists of Tangible Ephemera specifically to negate ambient photon recursion. A sheet of Basalt Vellum left unweaved in a lamp-lit reading room will yellow slightly at the margins over roughly forty years. The discoloration is harmless, but it has been used in at least one audit to date a document, wrongly.

Two Rulings

Dispute over the material's proper use is old. The Eleventh Concordance, Annex 2, holds that "any inscription struck upon stone shall be taken as final at the moment of striking, and no emendation shall be attempted without a new sheet" (Eleventh Concordance, Annex 2, clause iii). The Nineteenth Concordance permits amendment by re-grinding, provided the earlier text be "recorded in a working hand before the surface is taken down" (Nineteenth Concordance, Annex 9, clause i). The two provisions have never been reconciled. In practice the Office of Inscribed Corrections applies the older rule to ceremonial sheets and the newer to registers, and says so plainly when asked.

The second ruling concerns temperature. Basalt Vellum contracts measurably below 4 degrees. Following the Frost Recension of Cycle 12, sheets stored in unheated galleries were found to have shed their inscription flakes onto the floor below, an incident recorded in the Vellum Rotunda inventory for that winter and attributed, after some acrimony, to draughts.

"The stones were not damaged. The stones had parted with what was on them, as was their right under the older reading. We recovered the flakes in a tray."

— Clerk-Adjutant Merrin of the Sixth Grind, deposition to the Chapter of Inscribed Corrections, Cycle 12

Audit and Descent

Basalt Vellum is surrendered for audit in the same manner as paper stock, under Vellum Descent regulations, although the ritual is abbreviated: the sheet is weighed rather than unfolded, and the weighing is recorded against the holding of the Vellum Originals Repository rather than the Vellum Stacks. Where the Vellum Rotunda receives a mixed deposit of paper and stone, the stone is stacked separately. Sheets must not be stacked more than nine deep. A tenth sheet compresses the lacing of the lowest.

Whether Basalt Vellum ought to be governed as standard issue or as mineral stock has been raised at every audit since Cycle 14. The Cycle 14, Vellum returns list it under both headings, which has the effect of doubling its apparent holdings; the Central Vellum Repository has declined to correct the returns, noting that the discrepancy has been stable for long enough to be relied upon. See also 14 Vellum, which is a quantity, not a grade.