"hopper crystal" meaning in English

{
  "forms": [
    {
      "form": "hopper crystals",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "hopper crystal (plural hopper crystals)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Mineralogy",
          "orig": "en:Mineralogy",
          "parents": [
            "Geology",
            "Earth sciences",
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A mineral crystal whose interior space is empty"
      ],
      "id": "en-hopper_crystal-en-noun-smJuPmLT",
      "links": [
        [
          "mineralogy",
          "mineralogy"
        ],
        [
          "mineral",
          "mineral"
        ],
        [
          "crystal",
          "crystal"
        ]
      ],
      "raw_glosses": [
        "(mineralogy) A mineral crystal whose interior space is empty"
      ],
      "topics": [
        "chemistry",
        "geography",
        "geology",
        "mineralogy",
        "natural-sciences",
        "physical-sciences"
      ],
      "translations": [
        {
          "code": "it",
          "lang": "Italian",
          "sense": "Translations",
          "tags": [
            "feminine"
          ],
          "word": "tramoggia"
        }
      ],
      "wikipedia": [
        "hopper crystal"
      ]
    }
  ],
  "word": "hopper crystal"
}

{
  "forms": [
    {
      "form": "hopper crystals",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "hopper crystal (plural hopper crystals)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "Translation table header lacks gloss",
        "en:Mineralogy"
      ],
      "glosses": [
        "A mineral crystal whose interior space is empty"
      ],
      "links": [
        [
          "mineralogy",
          "mineralogy"
        ],
        [
          "mineral",
          "mineral"
        ],
        [
          "crystal",
          "crystal"
        ]
      ],
      "raw_glosses": [
        "(mineralogy) A mineral crystal whose interior space is empty"
      ],
      "topics": [
        "chemistry",
        "geography",
        "geology",
        "mineralogy",
        "natural-sciences",
        "physical-sciences"
      ],
      "wikipedia": [
        "hopper crystal"
      ]
    }
  ],
  "translations": [
    {
      "code": "it",
      "lang": "Italian",
      "sense": "Translations",
      "tags": [
        "feminine"
      ],
      "word": "tramoggia"
    }
  ],
  "word": "hopper crystal"
}