Hardness of gems

The Mohs scale rates the hardness of materials, and is based on these minerals (from softest to hardest):

Talc Gypsum Calcite Fluorite Apatite Feldspar Quartz Topaz Corundum Diamond

Trumpets give chilling forms after frigid queens twirl crimson dice
Tacos grab complicated foreigners after friendly questions train creepy dietitians
Tall gleeful careless fantastic architects flail quick tiny cyan doilies

Dicarboxylic acid

These are a type of organic compound. The first six are:

Oxalic Malonic succinic glutaric adipic pimelic

The "common" mnemonic is: Oh my, such great apple pie!

We also came up with:
objective mean sponges grab athletic pajamas
odious mad shepherds gulp airborne peas

Petroleum products

These are some common byproducts are obtained by petroleum distillation but may be used outside the refining industry.

LPG petroleum kerosene diesel fuel lube bitumen

lazy public kites defend foxy lovesick buses

Properties of metals

Some, but not all, properties of metals. "Dense" frequently makes the list also.

hard shiny malleable ductile conductors

hollow spiders measure drugged caterpillars
happy sheep mangle dreamy cars
holy sunflowers make dictatorial customers