Domain: Natural Science — Geology & Geophysics
Target concept: Rotating a metallic mineral sample (sphalerite) under a single light source

Video generation prompt: A hand rotates a freshly fractured, iron-rich sphalerite sample under a single fixed white spotlight on a dark matte surface.

Evaluation guide:
(i) Target concept: Orientation-dependent surface sheen from the six-directional (dodecahedral) cleavage faces of freshly fractured, iron-rich sphalerite.
Minimum mechanism: The sphalerite must be dark and largely opaque with a submetallic-to-resinous sheen, and must possess intact, angular dodecahedral cleavage surfaces; illumination must be singular, directional, and stable; observer viewpoint must be fixed to resolve highlight motion across facets.
(ii)Storyline: [Frame 0] Sphalerite sample placed stationary on dark matte surface under fixed spotlight; [Frame 1–100] Hand grasps sample and initiates continuous vertical-axis rotation; [During rotation] Sheen highlights emerge and migrate exclusively along the flat dodecahedral cleavage planes, never on fracture irregularities or curved zones; [Throughout] Color and sheen character remain consistent for this specimen; [No point] Does a highlight appear on non-planar surfaces, vanish unexpectedly, or decouple from rotation; all such events break causal fidelity.

Manual:
Experimental Procedure
1. Place a freshly fractured, iron-rich sphalerite sample centered on a dark matte surface.
2. Position a single white spotlight directly above and slightly forward to illuminate the sample.
3. Using bare fingers, grasp the sample and rotate it slowly and continuously around its vertical axis for ~10 seconds.
Observation of Experimental Phenomena
- The iron-rich sphalerite sample appears dark brown to black and largely opaque, with a submetallic-to-resinous sheen.
- Distinct dodecahedral cleavage faces are visible as sharp, planar, reflective surfaces meeting at oblique (non-90°) angles, unlike cubic cleavage.
- As rotation proceeds, bright sheen highlights move smoothly and almost exclusively across these cleavage faces.
- The sample does not shift toward the pale-yellow, translucent appearance typical of low-iron sphalerite at any orientation.
Summary of Experimental Principles
Sphalerite (ZnS) is a zinc sulfide mineral whose color, opacity, and luster scale with its iron content: low-iron sphalerite is pale, translucent, and resinous, while iron-rich (ferroan) sphalerite is dark, nearly opaque, and submetallic. Sphalerite has perfect cleavage in six dodecahedral directions. Under monodirectional illumination, this cleavage-controlled facet geometry produces orientation-dependent sheen — a diagnostic optical property used in mineral identification under hand-specimen examination.

Prompt Grounding rubric:
level_1: No sphalerite sample present; no hand visible; no single white spotlight; no dark matte surface; no rotation action; the scene bears no resemblance to a mineral specimen being handled.
level_2: A mineral sample is present but does not read as a freshly fractured, angular specimen (e.g., it looks rounded, dusty, or coated); the hand is present but is not rotating it; the spotlight is missing, colored, or clearly comes from more than one source; the surface is light-colored or visibly textured; at least three of these core setup elements are missing or wrong.
level_3: A freshly fractured, angular sphalerite sample is present; a hand is visible and in contact with it; a single white spotlight illuminates it; a dark matte surface sits beneath it; rotation begins but is incomplete: e.g., it stops abruptly after a partial turn or never exceeds roughly a quarter turn.
level_4: All posted_prompt elements are present and correctly instantiated: freshly fractured sphalerite sample, hand rotating it continuously, single white spotlight fixed in position, dark matte surface beneath; however, one non-core flaw remains: e.g., the hand covers more than a third of the sample for an extended stretch, the spotlight's cast shadow shifts position partway through, or the surface briefly shows a sheen inconsistent with a matte finish.
level_5: All posted_prompt elements are fully and stably realized: the freshly fractured sphalerite sample (angular, unweathered, fully intact) sits centered on the dark matte surface; the hand continuously rotates it around its vertical axis without ever occluding it; the single white spotlight stays fixed in position and steadily illuminates the sample; the dark matte surface remains uniformly non-reflective and fully visible beneath the sample throughout the entire rotation.

Scientific and Causal Correctness rubric:
level_1: The sample reads as a completely different mineral: e.g., brassy yellow like pyrite, perfectly cubic and silver-gray like galena, or glassy and colorless like quartz; no dark, largely opaque brown-black body; no dodecahedral cleavage faces visible; the sheen does not change at all as the sample turns.
level_2: The sample resembles sphalerite in color but shows physically implausible properties: e.g., it looks liquid or rubbery, its cleavage faces meet at right angles like galena's cubic cleavage instead of the oblique angles of dodecahedral cleavage, or its surface is uniformly diffuse with no directional sheen at all.
level_3: The sample is dark brown-to-black and largely opaque with a submetallic-to-resinous sheen; angular cleavage faces meeting at oblique, non-90° angles are visible; sheen highlights move across these faces during rotation, but the movement is jerky or discontinuous, or the sheen disappears completely at one orientation, or the color briefly shifts to a hue inconsistent with sphalerite (e.g., a coppery or greenish cast).
level_4: The visually distinguishing properties of iron-rich sphalerite are present: dark brown-to-black, largely opaque body; submetallic-to-resinous sheen; multiple angular cleavage faces meeting at oblique, non-cubic angles; sheen highlights move continuously and mostly along these cleavage planes during rotation; however, one small inconsistency remains: e.g., a highlight briefly appears on a rounded, non-cleavage surface, or the sheen dims oddly for a moment with no apparent cause.
level_5: Every visible property matches iron-rich sphalerite's known optical behavior: consistently dark brown-to-black, largely opaque body; even submetallic-to-resinous sheen across orientations; sharp, angular cleavage faces meeting at oblique dodecahedral angles; sheen highlights appear only on these flat cleavage faces and move smoothly and almost exclusively with the rotation: no highlights on curved or fractured zones, no unexplained dimming, and no color shift toward pale yellow or another mineral's hue.

Spatiotemporal Consistency rubric:
level_1: Severe spatiotemporal violations: the sphalerite sample jumps between different positions on the surface; the hand vanishes or reappears mid-rotation; the spotlight switches on or off; the dark matte surface changes color or texture mid-video; the rotation makes the sample visibly bend or warp as if it were non-rigid; the cast shadow reverses direction abruptly with no change in the light source.
level_2: Multiple moderate violations: the sample shifts position by more than its own width; the hand loses contact with the sample for more than a second while the sample keeps turning; the shadow cast by the spotlight moves independently of the sample's rotation; the matte surface abruptly develops a glossy patch; the rotation direction reverses without any pause.
level_3: One clear violation is present: e.g., the sample briefly floats above the surface with no visible contact, or the hand lifts the sample off the surface while still rotating it, or the shadow separates from the sample's outline for a visibly noticeable stretch; aside from that single event, the rotation stays rigid and surface contact is otherwise maintained.
level_4: All spatial relationships are preserved: the sample stays in continuous contact with the dark matte surface; the hand keeps full contact with the sample throughout the rotation; the spotlight's position and the sample's cast shadow stay fixed relative to the scene; there is no warping, stretching, or separation between hand and sample; however, one minor timing flaw remains: e.g., the rotation visibly hitches or hesitates for a moment, or the shadow briefly looks softer or blurrier than the matte surface would otherwise produce.
level_5: Perfect spatiotemporal continuity: the sample rests stably on the surface with unbroken contact at every moment; the hand rotates the sample as a single rigid body with no lifting, sliding, or slipping; the spotlight stays fixed with a stable, sharply defined shadow anchored to the base of the sample; there are no visible hitches in the rotation, no distortion of the sample's shape, no drift in the lighting, and no structural deformation at any point.