Natural Spessartite has an orange color, but iron impurities are usually present, which give it an reddish-orange or brownish-orange color. Pure orange Spessartite is not common; reddish, brownish or yellowish tints are frequent. Its most desirable color is a fiery-red with slight orange tints. Spessartite has an exceptionally high refractive index, giving cut Spessartite gemstones a special brilliance.

Once fairly uncommon in gem-grade transparent specimens, many new deposits of large facetable Spessartite crystals with excellent color have been discovered, are are making this form of Garnet more readily available and mainstream. A very important deposit of this gemstone was discovered in the 1960's in the Umba River Valley of Tanzania and Kenya. The trade name of Malaya Garnet (or Malaia Garnet) was coined to describe these new African Garnets. Malaya Garnets are not pure Spessartite, but are intermediary between Spessartite and Pyrope, though closer in chemical composition to Spessartite.