Gravel Stone Seal is a Sacred Seal in Elden Ring. The Gravel Stone Seal scales primarily with  Faith and is a good Weapon for casting lightning related incantations. 

Elden Ring Gravel Stone Seal Notes & Tips

• Skill: None
• This weapon cannot be infused with Ashes of War
• Gravel Stone Seal can be upgraded by using Smithing Stones
• Buffs damage of Dragon Cult Incantations by 15%
• Wielding the two of the seals at the same time will allow the damage increase to stack.
  • Seems to be a multiplicative increase for a roughly 32% total damage increase.
  • On NG with pure FTH build and 60+ FTH, Erdtree Seal +10 is better than Gravel Stone Seal
  • On NG+ (or NG with trade) 2 Gravel Stone Seals are slightly better than Erdtree Seal +10 and Gravel Stone Seal offhand
• Spellbuff of 282 at +25 with 60 Faith; 318 at +25 with 80 Faith; 343 at +25 with 99 Strength and 99 Faith.
• Dragon Cult Incantations include: Ancient Dragons' Lightning Spear, Ancient Dragons' Lightning Strike, Honed Bolt, Frozen Lightning Spear, Lightning Spear, Lightning Strike, Fortissax's Lightning Spear, Lansseax's Glaive, and Death Lightning.
• Sell Value:  

   100

• NOTE: As of Patch 1.08 a bug that prevented the follow-up attack from occurring when the Black Sword Incantation was activated with a Sacred Seal in the left hand has been fixed.
• NOTE: As of Patch 1.09, the scaling values of this weapon were changed. Please refer to the Upgrades Table of this weapon below.
• Other notes and player tips go here

Gravel Stone Seal PvP Poise Damage Values in Elden Ring

Patch 1.10 adjusted PVP Poise Damage of all Weapons including some Spells and Incantations. Please take note that these adjustments are exclusive to PVP.