Cheapest priced copy (Commander Legends: Battle for Baldur's Gate): $1.29 at Card Kingdom, near mint, their price list as of .
Stonespeaker Crystal 
Artifact · Uncommon · Star Trek Commander · #500
{T}: Add {C}{C}.
{2}, {T}, Sacrifice this artifact: Exile any number of target players' graveyards. Draw a card.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
4 printings · $1.29 to $1.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander Legends: Battle for Baldur's Gate | 338 | Uncommon | $1.29 | $1.49 |
| Commander Legends: Battle for Baldur's Gate | 450 | Uncommon | $1.29 | $1.99 |
| The List | CLB-338 | Uncommon | — | — |
| Star Trek Commander | 500 | Uncommon | — | — |
2 rulings from Wizards of the Coast
- 10 June 2022You choose any number of target players as you put Stonespeaker Crystal's ability on the stack and exile their graveyards as it resolves. You may not target a player and then choose not to exile their graveyard.
- 10 June 2022You may choose to target no players while activating the last ability if you just want to draw a card.