| name | cut-gemstone |
| locale | wenyan-ultra |
| source_locale | en |
| source_commit | 82c77053 |
| translator | Julius Brussee homage — caveman |
| translation_date | 2026-04-19 |
| description | Cut gemstones using cabochon and faceting techniques. Covers rough assessment, orientation for optimal color and yield, dopping, cutting angles, and crown/pavilion geometry for standard brilliant cuts. Use when you have rough gemstone material to cut into a cabochon or faceted stone, planning cutting orientation for optimal colour or optical phenomena, setting up a cabbing or faceting machine, or selecting the appropriate cutting approach for a given material.
|
| license | MIT |
| allowed-tools | Read |
| metadata | {"author":"Philipp Thoss","version":"1.0","domain":"lapidary","complexity":"advanced","language":"natural","tags":"lapidary, cutting, faceting, cabochon, gemstones"} |
切寶石
自原以雞心與刻面法切寶石，含原評、向計、膠、磨、刻面幾。
用
- 有原欲切為畢雞心或刻面石
- 需計切向為佳色、產、光象
- 首設雞心或刻面機
- 欲曉標亮切冠與底角
- 需為材擇合切法
入
- 必：原寶石（已識種——見
identify-gemstone）
- 必：切法決：雞心或刻面
- 必：目形與約寸
- 可：鑽刃修鋸
- 可：80/220/600/1200/3000 目輪之雞心機
- 可：含索齒、桅、盤之刻面機
- 可：膠蠟或環氧、膠棒、酒精燈
- 可：標校寸（橢、圓、馬眼）模
行
一：原評與安察
切前評原材。
Rough Assessment Checklist:
+--------------------+------------------------------------------+
| Factor | Assessment |
+--------------------+------------------------------------------+
| Species | Identified? (MANDATORY before cutting) |
| | Toxic dust risk? (check below) |
+--------------------+------------------------------------------+
| Fractures | Internal fractures that limit yield? |
| | Will the stone break during cutting? |
+--------------------+------------------------------------------+
| Colour zones | Where is the best colour concentrated? |
| | Can the cut centre the colour? |
+--------------------+------------------------------------------+
| Inclusions | Large inclusions that should be cut away?|
| | Silk for star stones? (orient for star) |
+--------------------+------------------------------------------+
| Size and shape | What finished shapes fit this rough? |
| | Calibrated size possible? |
+--------------------+------------------------------------------+
| Yield estimate | Approximate finished weight as % of rough|
| | Typical: 25-40% for faceting |
| | Typical: 40-60% for cabochons |
+--------------------+------------------------------------------+
SAFETY — TOXIC DUST MATERIALS:
These minerals produce hazardous dust when cut. Use wet cutting ONLY,
ensure ventilation, and wear an appropriate respirator:
- Chrysotile (asbestos serpentine) — NEVER cut dry
- Malachite — copper carbonate dust is toxic
- Cinnabar — mercury sulfide, extremely toxic
- Orpiment/Realgar — arsenic compounds
- Chrysocolla — copper silicate, moderate risk
- Tiger's eye (fibrous) — fine silica fibers
ALL stone cutting produces silica dust. Always use water cooling
and never grind or cut dry without a dust extraction system.
- 確種識（疑則先行
identify-gemstone）
- 察毒塵險——某材需額外防
- 強透光下察裂
- 映色區與內含位
- 估原可生之畢形
得： 原評備含種確、裂映、色識、切謀成。
敗： 原廣裂→考可穩（多孔材環氧浸）或產過低不值切。某原勝售或換為標本材。
二：向計
定色與象之最佳切向。
Orientation Principles by Stone Type:
PLEOCHROIC STONES (tourmaline, sapphire, tanzanite, iolite):
- Orient the table perpendicular to the crystal axis showing
the best face-up colour
- Tourmaline: the c-axis often shows dark/opaque colour —
orient the table to view the a/b axis colour
- Sapphire: slight pleochroism — orient for deepest blue face-up
- Tanzanite: trichroic — blue/violet axis preferred for table
STAR STONES (star ruby, star sapphire):
- Silk (rutile needles) must be parallel to the base
- Cut as cabochon with the dome centred over the silk
- The star appears at 90 degrees to the silk orientation
CAT'S EYE STONES (chrysoberyl cat's eye, tiger's eye):
- Fibrous inclusions must run perpendicular to the length
of an elongated cabochon
- The eye appears as a bright line across the shortest dimension
COLOUR-ZONED MATERIAL (sapphire, ametrine, watermelon tourmaline):
- Position colour zones so they are not visible face-up
- Or feature them intentionally (ametrine, watermelon tourmaline)
- 定石含多色否——自多向以二色鏡察
- 象石（星、貓眼）—尋含模向
- 色區材——決隱或顯區
- 以鋁筆於原標向
- 計檯位與深為擇向最大產
得： 含標檯向、向、約輪之原石。切謀優色現與產。
敗： 最佳色向衝最大產→按優先決：色質幾恆增值勝加克重。疑則向色。
三：雞心切
於雞心機塑石為凸雞心。
Cabochon Cutting Sequence:
EQUIPMENT SETUP:
- Cabbing machine with water drip on all wheels
- Wheel sequence: 80, 220, 600, 1200, 3000 (or 1200 + polish)
- Dop sticks and dop wax (or cyanoacrylate adhesive)
- Safety glasses — MANDATORY
- Avoid loose clothing, tie back long hair
STEP-BY-STEP:
1. SLAB: Cut a slab 5-8mm thick through the best area
2. TEMPLATE: Mark the desired outline (oval, round, etc.)
using a template and aluminum pencil
3. TRIM: Remove excess material on the trim saw or 80-grit wheel
Cut close to the line but leave 1-2mm margin
4. DOP: Attach the slab to a dop stick with dop wax
Heat the wax, press the stone flat-side down, centre it
5. SHAPE (80 grit): Grind to the template outline
Work all the way around, maintaining symmetry
6. DOME (220 grit): Shape the dome profile
Standard dome height = ~1/3 of the stone's width
Keep the dome symmetrical — check from all angles
7. SMOOTH (600 grit): Remove 220-grit scratches
Work systematically, keeping even pressure
8. PRE-POLISH (1200 grit): Remove 600-grit scratches
The surface should feel smooth to the fingernail
9. FLAT BOTTOM: Remove the stone from the dop, re-dop
face-down, and grind the bottom flat on 220 → 600 grit
10. POLISH: See polish-gemstone skill for final finishing
- 設雞心機含諸輪水流
- 戴安鏡——無例
- 切板而標模輪
- 穩膠石——磨中松石險
- 80 目磨形、220 凸、600 至 1200 平
- 保凸續均勻——凸不均於磨後現「平點」
得： 勻凸雞心備為終磨、含稱輪、均凸高、無 1200 目階之見痕。
敗： 凸含平點或不稱→返 220 目再塑。失少材勝磨不均凸。石磨中離膠→慎重膠續——先察石為缺。
四：刻面
以刻面機切精幾面。
Standard Round Brilliant Angles (quartz-family, RI ~1.54):
+------------------+-------+--------+
| Facet | Angle | Index |
+------------------+-------+--------+
| Crown main | 42° | 96-index: 3,9,15,21,27,33,39,45 |
| Crown break | 25° | (bisect mains) |
| Crown star | 15° | (bisect breaks toward table) |
| Table | 0° | flat |
| Pavilion main | 43° | 96-index: 3,9,15,21,27,33,39,45 |
| Pavilion break | Use GemCad or published diagrams |
+------------------+-------+--------+
Standard Round Brilliant Angles (corundum, RI ~1.76):
+------------------+-------+
| Facet | Angle |
+------------------+-------+
| Crown main | 37° |
| Pavilion main | 41° |
+------------------+-------+
CRITICAL: Pavilion angles determine brilliance.
- Too shallow → light leaks through bottom ("windowing")
- Too steep → dark extinction zones
- Correct angle → total internal reflection (brilliance)
- 為目形與材 RI 擇刊刻面圖
- 備原：平底側（尖底朝下）
- 膠石——圓石用錐膠、他用平膠
- 粗盤（600 目鑽）先以刊角切底面
- 諸底面至精點（「底尖會」）
- 轉至錐膠（或用轉夾）切冠
- 先冠主、後破、後星、終立檯
- 各層預磨與磨（見
polish-gemstone 擇盤與複合）
得： 刻面石含精會（面緣合於單點）、一致面寸、善稱、材 RI 合角。
敗： 會偏→角或索設略誤。復察刊圖。「追會」（調一面修他）積誤——誤大時勝重切層。小會誤初者常、不顯影光。
五：切後察
終磨前評切石。
- 徹淨石
- 察稱：上觀（輪）、側觀（比）、透檯觀（會精）
- 雞心：驗凸均、察平點、確輪形一致
- 刻面：10x 鏡下察會、察切階餘面痕
- 量終寸與重
- 見缺→磨前返合切步
得： 全切石合稱、會、面備之質準、備為磨階。
敗： 顯缺見（稱差、會差、比誤）→現重切勝磨缺石後重切。記誤為下石。
驗
忌
- 切無識石：某材生毒塵（孔雀石、朱砂、石棉）。切前恆識。恆水冷
- 略向計：多色石不向色致畢寶暗或誤色、本可正向得美
- 乾磨：乾磨生矽塵（慢健險）且熱石（熱震或裂）。諸輪盤水續流
- 躍階：躍 220 至 1200 目遺深痕磨後現。各目階須全除前階痕
- 膠敗：膠黏不足石磨中移或飛。用足蠟、保石暖（非冷）、膠涼盡方磨
參
identify-gemstone — 切前須種識polish-gemstone — 切後次步，含盤擇、複合擇、終磨
