garnet. There are lots of different types of garnet. I generally think of these as a small crystalline red-brown rock.
Picture from Wikipedia
quartz (silicon dioxide SiO2.)
(Picture from Wikipedia.)
made of or from opal (Hydrated silica. SiO2·nH2O).
Names of substances, including minerals, are generally given in the stative, as they are considered to be attributes. A piece of opal would be referred to with the singular jarākerel.
pa jakīþa anrākerel;
The rock contains opal.
More literally, the rock has an attribute: opal.
la jakīþa jarākerel;
The rock is opal. (or, The opal rock is.)
A picture (by me, taken in Australia):
of food, having salt (NaCl) added to it, salted.
of any substance, having a quantity of salt (NaCl and others); tasting brackish or salty.
For example, anhāri anracōi is ‘salt water’ as opposed to fresh water, and annāmmi ancōi is ‘salted water’ for swishing around one’s mouth when one has a toothache or a sore.
salt (NaCl) crystals for eating.