Is there anyone who is very knowledgeable about Elite Shungite?

This is confusing. The top necklace is a Rare and Organic Elite Shungite Tumbled Bead Necklace 18" in sterling silver 295.00 ctw (carats total weight), total weight in grams is 59.80, and product weight is 0.800 which I assume is the Shungite and Silver respectively. The bottom necklace is an Elite Shungite Round Beaded Necklace cut finished, and polished, not faceted adjustable (by about 2", about 18'- 20") in Platinum over Sterling Silver 150 ctw, tw gr 72.50, and product wt gr is 2.580. This is my confusion. Why is the 295 ctw & (59.80 gr Shungite) just tumbled top necklace with the more carat weight weigh less gram-wise than the bottom necklace that has been finished more at 150.00 ctw, and (72.50 gr Shungite) it also costs $80 more too (probably because it looks better)? Can anyone explain the carrot weight vs gram weight disparity, please? Trying to understand Shungite and gemstones in general.