scapolite group

noun

: a group of minerals crystallizing in the dipyramidal class of the tetragonal system, being white or grayish white in color when pure, and consisting essentially of silicates of aluminum, calcium, and sodium (hardness 5–6.5, specific gravity 2.5–2.8)

Love words?

You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Start your free trial today and get unlimited access to America's largest dictionary, with:

• More than 250,000 words that aren't in our free dictionary
• Expanded definitions, etymologies, and usage notes
• Advanced search features
• Ad free!