# TWSBI Obsidian Fountain Pen (Limited Edition) - Mixed black resin with rose gold trim and nib

## TWSBI Obsidian Fountain Pen

A limited edition piston filler with a darker, more architectural presence than anything in the standard TWSBI line. 

The Obsidian moves away from full transparency and instead introduces a marbled black resin body with rose-gold toned accents, creating a pen that feels grounded, refined, and deliberately composed. It still carries TWSBI’s engineering focus, but with a more curated, less clinical personality.

## What sets it apart

-   Obsidian resin with subtle marbling for depth and variation
-   Rose-gold toned trim for warmth against the dark body
-   Built-in piston filling system for high ink capacity
-   Ink window discreetly integrated into the design   
    
-   Shares same smooth nib as the Diamond 580 

### How it feels in use

The Obsidian feels more substantial and composed than transparent piston pens. The marbled body softens the mechanical nature of the filling system, while the rose-gold accents add a quiet contrast rather than shine.

### Who it’s for

-   Writers who want a piston filler with a more premium visual identity
-   Users who like darker, stone like materials rather than demonstrators
-   Journalers and note takers who prefer a more grounded writing experience
-   Collectors of limited edition TWSBI releases  
    

### Not for

-   Users who prefer fully clear demonstrator pens
-   Those who want ultra light or pocket sized pens
-   Writers who avoid any form of pen maintenance
-   People who prefer bright, highly saturated colour designs

### Practical tips

-   This is a piston filler designed for regular flushing rather than full disassembly in daily use. Keep cleaning simple and consistent if you rotate inks often.

### FAQs

**Is it a demonstrator?  
**No. Unlike many TWSBI pens, the Obsidian uses a marbled resin body rather than a fully transparent barrel.

**Does it use cartridges?  
**No. It uses an integrated piston filling system and is designed exclusively for bottled ink.

**Is it beginner friendly?  
**Yes. Despite its premium positioning, it uses the same straightforward piston mechanism found across the TWSBI range.

**Is it fragile?**  
Not inherently. It is designed for everyday use, though like all piston fillers, it benefits from basic care and regular cleaning.

### What’s included

-   TWSBI Obsidian Fountain Pen
-   Wrench
-   Silicone grease
-   Presentation box
-   Instruction leaflet
-   [Free nib tuning](https://www.larrypost.com.au/blogs/blogs/smooth-writing-with-fountain-pens?_pos=2&_sid=a2392eaaf&_ss=r) from LarryPOST  
    

### Ink pairing suggestions

-   Deep blacks and blue-blacks for an “inkstone” feel
-   Dark greens and forest tones to bring out the organic marbling
-   Warm browns and sepias to complement the rose gold trim  
    

### Build your practice

-   Use with [Twsbi Diamond Ink Well](https://www.larrypost.com.au/collections/larrypost-brands-twsbi?filter.p.product_type=Fountain+Pen+Ink+Well) for mess free filling  
    
-   [De Atramentis Document ink](https://www.larrypost.com.au/collections/larrypost-brands-de-atramentis?filter.p.product_type=Waterproof+Bottled+Ink) for permanence
-   Add a [Twsbi Pipe](https://www.larrypost.com.au/products/twsbi-pipe-needle-attachment-for-refilling-fountain-pens?_pos=1&_sid=4c8088925&_ss=r) as a useful attachment to fill from an almost empty ink bottle

### Specifications

-   **Brand:** TWSBI
-   **Brand series:** Limited Edition
-   **Launch:** Dec 2025
-   **Origin:** Taiwan
-   **Nib:** Stainless steel
-   **Nib sizes:** EF, F, M, B, 1.1 stub
-   **Filling system:** Piston filler (1.9mL)
-   **Body:** Mixed acrylic
-   **Trim:** Rose gold plated stainless steel
-   **Cap:** Twist
-   **Grip:** approx. 10mm
-   **Diametre:** approx. 15mm
-   **Length:** approx. 142mm (capped)
-   **Weight**: approx. 30g (capped)
-   **Comparable size:** TWSBI Diamond 580ALR, Pilot Custom 74, Lamy Studio

A more composed expression of TWSBI’s engineering, where performance stays familiar but the visual language is reserved.

## Details

- **Price:** 249.95 AUD
- **Vendor:** TWSBI
- **Type:** Fountain Pen
- **Tags:** Category_LarryPOST/Brands/TWSBI, Category_LarryPOST/Brands/TWSBI/Fountain Pen, Category_LarryPOST/Brands/TWSBI/New Limited Editions, Category_LarryPOST/Brands/TWSBI/TWSBI Kai, Category_LarryPOST/Brands/TWSBI/TWSBI Plated Editions, Category_LarryPOST/Brands/TWSBI/TWSBI Rose Gold, Category_LarryPOST/Education/2024 Fountain Day, Category_LarryPOST/Pens, Category_LarryPOST/Pens/Fountain Pen, TWSBI obsidian, TWSBI Obsidian Fountain Pen, TWSBI_Obsidian

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Extra Fine | 249.95 AUD | In stock |
| Fine | 249.95 AUD | In stock |
| Medium | 249.95 AUD | In stock |
| Broad | 249.95 AUD | In stock |

## Images

- TWSBI Obsidian Fountain Pen (Limited Edition) - Mixed black resin with rose gold trim and nib
- TWSBI Obsidian Fountain Pen (Limited Edition) - Mixed black resin with rose gold trim and nib
- TWSBI Obsidian Fountain Pen (Limited Edition) - Mixed black resin with rose gold trim and nib
- TWSBI Obsidian Fountain Pen (Limited Edition) - Mixed black resin with rose gold trim and nib
- TWSBI Obsidian Fountain Pen (Limited Edition) - Mixed black resin with rose gold trim and nib

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> Source: [LarryPOST](https://www.larrypost.com.au/products/twsbi-obsidian-fountain-pen-limited-edition-mixed-black-resin-with-rose-gold-trim-and-nib)
> Updated: 2026-07-04