Hard materials: metal, gold, glass, gems, stone, wood, bone

1. Order for any hard material (every source agrees): silhouette → base light + base shadow → backlight / secondary shadow → highlight or specular → reflection / refraction → clean-up (orphans, cracks, scratches). No texture before the form works.
2. Gloss decides the highlight. Matte (stone, wood, bone): none or very soft, low contrast, slow transitions. Glossy (glazed, plastic, wet): a 1–3 px specular, no long ramp. Metal and chrome: longer ramp, hard-edged bands, high contrast. Glass: transparency plus sudden white speculars. Wet surfaces: more speculars, details pop.
3. Mirror rule. A reflective surface is ordinary form-lighting plus a reflection layer painted on top. At ≤ 32 px draw 3–4 hard-edged bands in the scene's real colours (sky colour on top, a dark horizon band, ground colour below, one specular) — never a smooth ramp. The more reflective, the more saturated and contrasty the reflected world.
4. Metal: lights colder and less saturated, darks warmer and more saturated. Hue travel is tiny (steel ≈ +3°, S 7–24); the warmth comes from a different dark entry (violet/plum), not from rotating the whole ramp. Expect a strong rim or back light. Scratches, dents and wear tell the object's story. Metal is stiff: parts move individually, never stretch; animate the reflection by angle, not the shape.
5. Specular placement. 1–2 px at the top of the ramp, hue = light colour mixed ≈ 70/30 with the local colour; never #ffffff unless the object is a mirror or emitter. On a round object it may be a ring or crescent. It need not sit on the lit edge: a highlight on the far edge instead of a bevel makes a form feel solid, stone-like.
6. Gold is not orange. Dark entries are desaturated orange-brown (H 22–27, S 75, V ≈ 44), body yellow-orange (H 37–45, S 65–75, V 55–70), specular pale yellow. Reflections add a slightly paler or bluer band. If the palette has no true golden yellow (Resurrect 64's #f9c22b leans orange) switch ramp: Endesga 64 #edab50 #ffc825 #ffeb57 or AAP-64 #bb7547 #dba463 #f4d29c #ffd541 #fffc40.
7. Glass: show the world through it. The cheapest read of "see-through" is a border-only container; add 2–3 tiny slightly curved highlights, one tinted lighter band, shade away from the highlight, and let the background show. Never fill it opaque. The shadow of glass has a bright core streak (focused light).
8. Gems are flat facets, each one value. Anatomy: table, crown, girdle, pavilion; cuts brilliant, cushion, cabochon (smooth dome — a ramp, no facets). Light a facet whole. The shadow side takes a "refraction" step: warmer or more saturated, one step, not darker. One point highlight (1 px) and one dark facet opposite it.
9. Gem shine animation: each facet flashes whole; the middle frames cover the largest area, eased; on cabochons a rounded spot travels with the same easing. 3–4 frames. A coin or flat metal: the spec travels along the edge, not across the face; a goblet gets two specs — move the edge one, hold the centre one.
10. Stone: plane grouping. Reduce the rock to four plane classes — top (lightest), side in half-light, front in dark half-tone, shadowed side — and give each plane one ramp entry (≤ 32 px). Chromatic greys: warm lit planes, cool shadows. Texture is ≤ 2-entry variation in the half-tone band only; keep highlight and core flat. Five clean colours beat a noisy texture.
11. Stone families decide shape and shine. Igneous: rounded, gas holes, porous, very soft highlights (granite speckled grey, basalt dark blue-grey, obsidian near-black glossy). Sedimentary: layered, softest, crumbles, big soft highlights (limestone tan, bauxite red-brown). Metamorphic: breaks in large chunks, strong highlights, big clean areas (marble white with veins, slate dark flat). Rock colour must suit the geology of the scene: grey stone in a red canyon looks wrong.
12. Cracks: thin cracks end in a lighter pixel, deeper cracks in a darker one (line weight applied to cracks). Moss goes in crevices. A 2–3 px bevel on a block: light edge top-left, 1 px dark edge bottom-right.
13. Wood: hue-shift the shadows toward crimson, slow transitions, don't overdo the highlight, no pillow shading. Planks: big shapes and bevels first, grain after, raise contrast at joins; grain lines are broken, never full length. Bark: individual scales lit as one shape. End grain: rings fade with distance from the cut face. Details: knots, nails, cracks, moss.
14. Bone is cream, not white. Hue 44–50, S ≤ 30; shadows go warm taupe → violet-brown. Matte: no specular. Skeleton icons keep the eye sockets as 2×2 dark blocks and drop everything else at ≤ 9 px.
15. Ice and snow (brief): six tones, snow only on up-facing faces, reflection glint crossing the ice planes; sunset snow takes pink lights and blue-violet shadows. Soft-matter snow detail in rules://23-materials-soft.

Other gem hues (derived): emerald and sapphire use the green and blue 5-step ramps from rules://20-color-for-pixel-art, with the refraction step moved 25–40° off the shadow hue.

Light upper-left. Chrome and gold share one band layout so the colour decides the material.

O = outline      #181425
D = horizon-dark #4a3340
G = ground-refl  #8d7a88
M = sky-mid      #8b9bb4
L = sky-light    #c0cbdc
W = specular     #ffffff
---
....OOOO....
..OOLLLLOO..
.OLWWLLLLLO.
.OLWMMLLLLO.
OMMMMMMMMMMO
OMMMMMMMMMMO
OMMMMMMMMMMO
ODDDDDDDDDDO
.ODDGGGGDDO.
.OGGGGGGGGO.
..OOGGGGOO..
....OOOO....

Steel ball: sky-light, sky-mid, dark horizon band, warm ground reflection, 3-px L-shaped spec at the top-left. Roles map to the scene's own sky and ground.

O = outline        #3b1f14
D = horizon-shadow #703c19
G = ground-refl    #a8723a
M = body           #b38936
L = sky-refl-light #ebcc6a
W = specular       #fffad1
---
....OOOO....
..OOLLLLOO..
.OLWWLLLLLO.
.OLWMMLLLLO.
OMMMMMMMMMMO
OMMMMMMMMMMO
OMMMMMMMMMMO
ODDDDDDDDDDO
.ODDGGGGDDO.
.OGGGGGGGGO.
..OOGGGGOO..
....OOOO....

Gold ball: same bands, warm ramp. The horizon shadow is orange-brown, the sky reflection pale yellow, the spec near-white yellow.

B = rim-light   #cdeef0
T = glass-edge  #6aa0b3
S = glass-shade #3f6f82
H = highlight   #dff3f4
W = specular    #ffffff
C = caustic     #c9f2f0
F = tint        #8fc3d1
---
....BBBB....
..BB....TT..
.B..HH....T.
.B.W......T.
B..H.......S
B..........S
B.........FS
B........FFS
.T......CFS.
.T.....CFFS.
..TT....SS..
....SSSS....

Glass orb: only the contour exists — bright upper-left rim, mid tint, darker lower-right rim; two curved highlights, a tint patch and a bright caustic where light focuses. The interior stays transparent.

O = outline-deep      #3f2832
P = highlight-refl    #ff97b1
W = point-highlight   #ffffff
L = highlight         #ff596a
M = midtone           #e43b44
S = shadow            #9e284b
F = shadow-refraction #7b2056
---
..OOOOOOOO..
.OPPLLLLMMO.
OPWLLLLLMMSO
OOOOOOOOOOOO
.OPPLLMMSSO.
.OPLLMMMSFO.
..OPLMMSFO..
...OLMSFO...
....OLFO....
.....OO.....

Brilliant-cut ruby, front view: crown facets over a 1 px girdle, pavilion converging to a point. Highlight reflection and point highlight upper-left, refraction step lower-right, deep colour only in the contour.

O = outline           #2a2633
T = top-plane-lit     #c4bdb0
M = front-plane       #948d8a
S = side-plane-shadow #6a687b
D = core-shadow       #454257
C = crack             #2a2633
K = crack-lip         #d9d3c6
---
....OOOO....
..OOTTTTOO..
.OTTTTTTTMMO
OTTTTTTMMMSO
OMMMMMMMSSSO
OMMCMMMMSSSO
OMMMCMMMSSDO
OMMMMKMSSDDO
.ODDDDDDDDO.
..OOOOOOOO..

Boulder as four planes: lit top, mid front, shadowed side, dark base. The crack runs 3 px and ends in a lighter chip.

O = bark-outline #422127
B = bark         #6b3f30
W = wood-light   #e0bb8b
R = ring         #996740
P = pith         #6b3f30
---
....OOOO....
..OOBBBBOO..
.OBBWWWWBBO.
.OBWRRRRWBO.
OBWRWWWWRWBO
OBWRWPPWRWBO
OBWRWPPWRWBO
OBWRWWWWRWBO
.OBWRRRRWBO.
.OBBWWWWBBO.
..OOBBBBOO..
....OOOO....

End grain: bark ring, light wood, two growth rings, pith. Flat face, so no ramp across it — the rings carry the form.

O = outline     #422127
L = bevel-light #e0bb8b
M = body        #c2966b
G = grain       #996740
S = shade       #6b3f30
N = nail        #e0bb8b
---
OOOOOOOOOOOOOO
OLLLLLLLLLLLLO
OMNMGGGGMMMMMO
OMMMMMMGGGGMMO
OMMGGGMMMMMMMO
OSSSSSSSSSSSSO
OOOOOOOOOOOOOO

Plank: 1 px bevel light on top, shade row at the bottom, three broken grain strokes at different lengths, one nail.

O = outline #422e37
L = light   #f7f3df
M = mid     #d6cbab
S = shadow  #a38c72
---
.OOO........OOO.
OLLLOOOOOOOOLLLO
OLLLLLLLLLLLLLLO
OMMMMMMMMMMMMMMO
OSSSMMMMMMMMSSSO
OSSSOOOOOOOOSSSO
.OOO........OOO.

Femur: two-lobed knobs, a shaft lit from above (light / mid / shadow rows), warm taupe shadow, no specular.

1. Pick the gloss class (rule 2) and the ramp from the table; load or write it with palette op set.
2. Block in the silhouette with the mid entry; look op preview — the shape must read before any band is drawn.
3. Draw base light and base shadow as planes or crescents (draw ops ellipse, polyline, fill, or grid from a template above).
4. Add the material layer: bands for metal/gold, border + highlights for glass, facet values for gems, plane entries for stone, grain and bevels for wood.
5. Place the specular last (1–2 px) with draw op pixels; skip it on matte materials.
6. Add one story detail only: scratch, crack, knot, chip. look op ascii to confirm no orphan pixels and no 2×1 doubles.
7. For shine or sparkle animation: duplicate frames with frame op duplicate, move only the spec/facet highlight, set frame op set_duration (3–4 frames, eased), check with look op filmstrip.
8. validate.

• The material is identifiable in a one-colour blob test and in colour: gloss class matches the highlight count and band hardness.
• Metal/gold use hard bands, not a smooth ramp; glass shows the background; gems are flat facets.
• Specular ≤ 2 px (≤ 4 px at 32+), not pure white unless mirror/emitter; none on stone, wood, bone.
• Stone uses one entry per plane; cracks end in a lighter or darker pixel; no orphan pixels.
• Shadows hue-shifted (wood toward crimson, stone cool, bone violet-brown), none are black.
• Light direction identical to the rest of the sprite.

• Saint11 (Pedro Medeiros) tutorials: Metal, Gems, Rock, Ice, Wood, Shine; Slynyrd Pixelblog PB13 "Rocks"; Rappenem, "Pixel Art Tutorial – Gold"; imonk's 24×24 health-potion tutorial; GameDevAcademy metallic pixel-art tutorial.
• Arne's painting tutorial (gold, gloss, glass), ENDESGA highlight notes; Pixel Logic (Ch. 3; pp. 167–172, 194: crack weight, metal edge rounding); Silber, Pixel Art for Game Developers (glass, brick, mug, stone wall, pp. 154–156, 196–197, 214–215).
• Gurney, Color and Light (mirror and glass rules, caustics, plane grouping, pp. 46, 160–165); Dawe, Make Your Own Pixel Art (damage by material, pp. 157–159).
• Measured ramps: Endesga 32/64, AAP-64, Resurrect 64, Lospec JSON; gold/gem samples read from the Saint11 sheets (noted as approximate).