This archive tracks four layers. A record present in 1 of them (IND) is silent in the rest, and says so.
The Horus HeresyM30–M31
[RECORD LOST]
No record for this location in The Horus Heresy.
Age of the ImperiumM32–M40
[RECORD LOST]
No record for this location in Age of the Imperium.
The 41st Millenniumpre-Rift
[RECORD LOST]
No record for this location in The 41st Millennium.
Era Indomituspost-Rift
contested
Imperial mining world besieged by the Emperor's Children
A rich world close to the Great Rift whose miserable population toils in darkness extracting precious minerals and working promethium refineries. Early in M42 the Daemon Primarch Fulgrim sets his scattered Legion the challenge of taking it, and the Perfecti warband of Knight-Commander Marduk Tamaris and the Sorcerer Lord Mauvais lay siege to its citadel, held by Cadian Shock Troops, Kasrkin, the local PDF and the Black Templars of Castellan Garrian and the Emperor's Champion Johannes Berengar. The setting of Fulgrim: The Perfect Son.
Position
Map frame: 815.8, 802.4 in the archive's 0–1000 disk space (core at 500, 500).
Distance from the core: 437 units ≈ 46.5k light years, south-east of the galactic core.
Height above the disk plane: -3.3 units — invented thin-disk jitter, deterministic per record. No published source gives any location a z coordinate.
System: Crucible System
Books set here
1 title in the reading tracker touches this record, 1 of them as a primary location. Titles link out to the tracker.
Every fact in this record, and where it came from. Editorial derivations say so.
identityhigh
wh40k.lexicanum.com/wiki/Crucible_(World ) (read directly in a browser on 2026-10-03): 'Crucible was a world of the Imperium close to the Great Rift' (Fulgrim: The Perfect Son, ch. 2); infobox Class 'Mining World'; 'a rich world where the miserable population toiled in darkness extracting precious minerals and Promethium refineries'; 'Sometime early in M42, Crucible was invaded by the forces of the Emperor's Children under Daemon Primarch Fulgrim and Knight-Commander Marduk Tamaris. The world was defended by Cadian Shock Troopers, Kasrkin, local PDF as well as Black Templars force under Castellan Garrian and Emperor's Champion Johannes Berengar' (chs 2, 6). Corroborated by Lexicanum Fulgrim:_The_Perfect_Son_(Novel) (Black Library's description, 'vanquish the Imperial world of Crucible') and Warhammer Community's Sunday Preview of 6 April 2025 and Saturday Pre-orders of 12 April 2025 ('the Imperial World of Crucible'). NAME-COLLISION CHECK: no index record uses the name or the id; Lexicanum's page is titled 'Crucible (World)', the disambiguation being from non-planet uses of the word.
segmentumhigh
null: the Lexicanum infobox leaves segmentum, sector, subsector and system blank and files the world under 'Segmentum Unknown'. 'Close to the Great Rift' is not a region this index can place: the Rift crosses the whole galaxy.
gposlow
inferred: the world is NAMED but canon never locates it, so the record claims no segmentum and sits on the unsurveyed rim at the generator's rim_xy('crucible') = [815.8, 802.4] (the function in build_locations.py evaluated on its own, which reproduces heliogabalus [930.6, 442.4], chevreuse [931.5, 388.0] and kallash [759.0, 848.6]; the script itself was not run). The position carries no information and must not be read as one. Z -3.3 is the zPolicy value (compute-z.mjs crucible 815.8 802.4).
classmedium
'forge', this dataset's industrial-extraction palette, from what the page says the world LOOKS like: a population toiling in darkness at mineral extraction and promethium refineries (Lexicanum Crucible_(World)). 'Mining World' is an economic tag, not a look; the piscina-iv, belmos-vii and dulma-lin precedents render an industrial extraction world as forge. 'fortress' was refused: the citadel is one defended city on the world, not the world.
erashigh
indomitus only: Lexicanum dates the invasion 'early in M42' and puts the world close to the Great Rift; no earlier history is published. Allegiance 'contested', the state the book spends its length in; the outcome of the siege is in the spoiler field, not the status.
systemIdlow
editorial: 'crucible', the world's own name; the Lexicanum infobox's System field is empty.
no-system-surveyhigh
No systems/crucible.json is authored, although Crucible is the book's primary setting: canon enumerates nothing about its system, no star, no sibling world, not even a body count or a system name, and an invented one-star-one-planet file would assert a star the sources never describe. The synthesiser draws the world from this record's class. Reopen if a permitted source names the star or another body.