Gymnocalycium mostii ssp.ferocior comes from Argentina's Le Rioja province. This is a small and slow growing plant, armed - or decorated, if you like - with thick ash-white spines. The little "egg in the basket" pictured here is of cause a flower bud. All Gymnocalycim flowers have these very recognizable scales on their buds and flower tube, and flower usually from the stem apex or near it.
The younger spines of cacti have that wet-glassy look as in the picture. Here they are also green and yellow-brown colored. Once fully developed the spines will become bone-white, turning ash-gray with age. Cactus spines considered to be from the plant anatomy view point bud scales, heavily meta-morphed. Like human hair, they grow from the bottom, not from the tip. Like on animal horns, you often can see growth rings on cactus spines.