Emily Dickinson word

The richest word I have found in the poem is "quartz", which is in the line "A quartz contentment, like a stone". In the dictionary, quartz is described as a "hard, crystalline mineral" which comes in a variety of colors. A crystal is a prism that refracts light like a rainbow, so it's beautiful, but quartz is also used in building when mixed with other minerals because it is so strong. So is the "quartz contentment" a reflection of something inside the speaker--beautiful like a crystal or strong like granite? This changes the interpretation of the poem because the tone before is depressing and melancholy. The way she describes the "wooden way" and "hour of lead" speaks to the numbness she feels while she is grieving. Lead is a heavy, dense element used in bullets or sinkers for fishing holes. Quartz to lead seems to show a progression in the stages of grief from clear and resonant to heavy and deadly. Before, she was falling apart and feeling nothing. Quartz could be thought of as stony demeanor or possibly her empty heart of stone. Or it could be seen as a turn in the poem, where she begins the second stage of grief and accepts it. Since a quartz reflects as a rainbow, we could think of it as the point where she begins to realize it will be okay and that it will not always be sadness and heartache. By using the word "quarts" the speaker is saying life is beautiful and that she is strong and resilient enough to accept and move on from the pain.