FMG's main turquoise page no longer includes the text I quoted but it still exists on on their website in other places.
It's a problem in the bead industry when a vendor's inaccurate descriptive name is taken verbatim as the correct name for a mineral.

My own business (Rings & Things) did it recently when we added a green bead with brown markings as the "Afghanistan jade" that the seller called it. It was not the same as the serpentine often called "Afghan jade" but it was very attractive and reasonably priced. On close inspection I discovered that it had a green coating that could be scraped off. The material under the coating was much less green but still had the brown and tan streaks.

We asked the vendor for more info. After a few back and forth emails they agreed it was coated and offered to send some "rough material" from which it was made. The sample of rough arrived - in the form of a strand of tan/off white beads that looked like the calcite sold as carvings in Mexico as "Mexican onyx."

In the case of "chalk turquoise" I fear FMG's buyers and catalog staff accepted the original descriptive name and never reconsidered it until their customers and my posts started to question the name and description.

Ya gotta be skeptical!