101Leafy researched the games.
Carbalite Sword

Made with an abundance of Carbalite steel in a classic shape. Very powerful.
Its conventional shape makes it easy to mistake for an Iron Sword at first glance, but its sharpness is on another level. The shine of the Carbalite Ore used in it so generously, unlike that of a Buster Sword, marks a refined hunter.
Our translation of 復刻 ハンター大全 (KADOKAWA / Enterbrain, 2014), page 144.
| Class | Great Sword |
|---|---|
| Rarity | 6 |
| Attack | 912 |
| Slots | 0 |
| Table price | 25,000z |
Upgrades
| Upgraded from | Chrome Razor |
|---|---|
| Upgrades into | Carbalite Sword+, Bronze Coin, Guardian Sword |
Can also be made new at the smithy.
Upgrade tree from モンスターハンターポータブル 2nd G 公式ガイドブック (Enterbrain, 2008), page 684.
Materials
Carbalite Ore ×5, Iron Ore ×50, Machalite Ore ×20
Plus Class Tcket ×1, Carbalite Ore ×1