CaEr₂La₇O₃Si₈

Architectural potential

A lanthanum-heavy rare-earth silicate with erbium and calcium as minor modifiers, fired at 1200 °C to 50 MPa at 5.91 g/cm³. No innovation flags accompany this entry, so the piece sits as a plain mass ceramic in a rare-earth matrix — which means the architectural argument has to be paid for in register rather than in function. The 50 MPa compression rules out any structural role; this is a surface or inlay tile at most. Natural placements are accent inlay patches in gallery thresholds where the dense rare-earth matrix reads as a quiet slow stone in contrast to the lighter carrier tile around it, detail insets in museum plinths, and small-area floor patterns in ritual interiors where the weight underfoot is the point. Against clay brick the carbon trade is three-times negative and no functional argument offsets it, which makes this one of the harder entries in the batch to specify honestly. Cost is the real caveat at €46.10 per 100 g batch, backed by a 300 g workshop ceiling — the piece lives in the single-signature-tile register and nothing larger. Untested in architectural production beyond the laboratory sample; a project using it does so as deliberate material research, not as a drop-in cladding.

Material character

Neutral reading — a warm off-white to pale fawn, carried by lanthanum silicate with the faintest rose undertone from the erbium fraction under daylight, a colour shift that only registers when a sample sits against a pure white reference. At 5.91 g/cm³ and 70×70×35 mm the slab is heavy for its footprint, insisting on two-handed lift off the bench, denser in hand than a standard fired-earthenware tile of the same face and close to the weight of a basalt cobble. Skin vitrified matte from the 1200 °C fire, close to a satin finish without crossing into glaze. Edges cold-cut, kerf pale. Fully opaque. Quieter in the hand than the vanadium-loaded Gd7O12V1 sibling — same firing tier, different colour temperament.