[No name given]

I’m wondering if they are pieces of the actual Cross which Jesus Christ was crucified on, and if so, I’m amazed they were able to preserve them.

[Vaquero]

Many so called relics were searched for and preserved by St Helena, mother of Constantine. More were dug up by the Knights Templar over the centuries. The authenticity of any of these is highly debated

[ifinnegan]

No.

[PGR88]

Emporer Constantine the Great’s mother, Helena, who was a devout Christian made a pilgrimage to Jerusalem in 326 - and supposedly found the “True Cross” (as well as those belonging to the two theives)

She commission a church built around them (The Church of the Holy Sepulchre) and there were, fragments of the True Cross distributed to various churches and kings around europe.

The True Cross was supposedly lost when Muslims burned the Church of the Holy Sepulchre in the 11th century

[PUGACHEV]

"I’m wondering if they are pieces of the actual Cross which Jesus Christ was crucified on, and if so, I’m amazed they were able to preserve them."

I suspect there is a chain of custody issue with the shards' provenance, so you either have to believe they are genuine or not.