428,604gp
434,000gp
-5,396gp
-13,968gp
—
—
Price history
1 points · hover for detail
- 30D low
- 428,604
- 30D high
- 434,000
- Volatility
- 1.3%
Flip calculator
Includes the 2% Grand Exchange tax
-13,968gp
-13,968 per item · -3.22% ROI
Tax puts break-even at 442,857 gp.
- Capital required
- 434,000 gp
- Gross revenue
- 428,604 gp
- GE tax (2%, 8,572/item)
- − 8,572 gp
- Break-even sell
- 442,857 gp
Item data
- High alchemy
- 24,900 gp94.2% below market
- Low alchemy
- 16,600 gp
- Shop value
- 41,500 gp
- Weight
- 1 kg
- Stack / note
- Not stackable · noteable
- Released
- Oct 26, 2017
About Black tourmaline core
The Black tourmaline core is a members-only item in Old School RuneScape.
"The blackened heart of the Grotesque Guardians"
Over the last 30 days it traded between 378,187 and 492,148 gp on the Grand Exchange, averaging 439,869 gp. About 93 units changed hands per day. The price is down 8.2% across that window. The Grand Exchange buy limit is 5 every 4 hours. Selling one at the average price costs 8,797 gp in Grand Exchange tax.
Casting High Level Alchemy returns 24,900 gp, which is 94.3% below the 30-day average price, so alching a bought one loses money.
How to get Black tourmaline core
Only Grotesque Guardians (1/1,000) drops Black tourmaline core.
Dropped by
| Monster | Rarity | Quantity |
|---|---|---|
| Grotesque Guardians | 1/1,000 | 1 |
Recipes
Where this item appears in crafting and processing.
Used to make
- 1× Guardian boots from 1× Bandos boots, 1× Black tourmaline core
Black tourmaline core price history
Daily averages rolled up per month, newest first.
| Month | Average | Low | High | Volume |
|---|---|---|---|---|
| October 202612d | 416,119 | 378,187 | 459,113 | 1,274 |
| September 2026 | 472,713 | 389,255 | 555,119 | 2,510 |
| August 2026 | 625,189 | 530,221 | 729,081 | 3,258 |
| July 2026 | 909,912 | 711,462 | 1,134,696 | 2,863 |
| June 202621d | 1,185,133 | 1,040,508 | 1,434,185 | 4,476 |
| May 20262d | 1,463,379 | 1,419,466 | 1,507,292 | 102 |
| April 20261d | 1,437,423 | 1,437,423 | 1,437,423 | 24 |
| March 2026 | 1,691,988 | 1,566,264 | 1,850,906 | 17,215 |
| February 2026 | 2,055,869 | 1,722,250 | 2,333,882 | 16,173 |
| January 2026 | 2,420,146 | 2,265,396 | 2,792,915 | 17,856 |
Across 10 months of recorded prices Black tourmaline core ranged from 378,187 gp in October 2026 to 2,792,915 gp in January 2026, measured over 218 trading days.
The 30-day average of 439,869 gp sits in the lower third of that range.
All prices in gp. Volume counts units traded across both sides of the Grand Exchange.