Chalk (Limestone Rock)

[SasquatchTortoise]

I was scrolling through the forum when I saw a few people mention something about giving or letting tortoises chew on chalk or high-calcium limestone for supplementation. Rock Chalk (not sidewalk chalk or climbing chalk, which sometimes has lead), as far as I am aware, is almost completely composed of Calcium Carbonate.
Wikipedia:
"Chalk is typically almost pure calcite, CaCO3, with just 2% to 4% of other minerals. These are usually quartz and clay minerals, though collophane (cryptocrystalline apatite, a phosphate mineral) is also sometimes present, as nodules or as small pellets interpreted as fecal pellets. In some chalk beds, the calcite has been converted to dolomite, CaMg(CO3)2, and in a few cases the dolomitized chalk has been dedolomitized back to calcite.[3]"

Any thoughts about this?

 

[Mr. RussianTortoise]

I was scrolling through the forum when I saw a few people mention something about giving or letting tortoises chew on chalk or high-calcium limestone for supplementation. Rock Chalk (not sidewalk chalk or climbing chalk, which sometimes has lead), as far as I am aware, is almost completely composed of Calcium Carbonate.
Wikipedia:
"Chalk is typically almost pure calcite, CaCO3, with just 2% to 4% of other minerals. These are usually quartz and clay minerals, though collophane (cryptocrystalline apatite, a phosphate mineral) is also sometimes present, as nodules or as small pellets interpreted as fecal pellets. In some chalk beds, the calcite has been converted to dolomite, CaMg(CO3)2, and in a few cases the dolomitized chalk has been dedolomitized back to calcite.[3]"

Any thoughts about this?

I'm no expert but are you talking about cuttlebones? Correct me if I'm wrong.

 

[SasquatchTortoise]

I'm no expert but are you talking about cuttlebones? Correct me if I'm wrong.

Well, chalk is technically the remains of very old sea creatures... I was mainly talking about the stuff that can be mined out of the ground.
that's partly why I was curious- Both are made of the same material (CaCO3), However Chalk is made of a form called calcite, and cuttlebone is formed as aragonite- a different molecular organization, if Google is to be believed.